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Tesi sul tema "Electron transport"

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Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 30 luglio 2024

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1

Foley, Simon Timothy. "Effects of electron-electron interactions on electronic transport in disordered systems". Thesis, University of Birmingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273932.

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2

Keall, Paul J. "Electron transport in photon and election beam modelling /". Title page, contents and introduction only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phk24.pdf.

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3

Kula, Mathias. "Understanding Electron Transport Properties of Molecular Electronic Devices". Doctoral thesis, KTH, Teoretisk kemi, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4500.

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his thesis has been devoted to the study of underlying mechanisms for electron transport in molecular electronic devices. Not only has focus been on describing the elastic and inelastic electron transport processes with a Green's function based scattering theory approach, but also on how to construct computational models that are relevant to experimental systems. The thesis is essentially divided into two parts. While the rst part covers basic assumptions and the elastic transport properties, the second part covers the inelastic transport properties and its applications. It is discussed how di erent experimental approaches may give rise to di erent junction widths and thereby di erences in coupling strength between the bridging molecules and the contacts. This di erence in coupling strength is then directly related to the magnitude of the current that passes through the molecule and may thus explain observed di erences between di erent experiments. Another focus is the role of intermolecular interactions on the current-voltage (I-V) characteristics, where water molecules interacting with functional groups in a set of conjugated molecules are considered. This is interesting from several aspects; many experiments are performed under ambient conditions, which means that water molecules will be present and may interfere with the experiment. Another point is that many measurement are done on self-assembled monolayers, which raises the question of how such a measurement relates to that of a single molecule. By looking at the perturbations caused by the water molecules, one may get an understanding of what impact a neighboring molecule may have. The theoretical predictions show that intermolecular e ects may play a crucial role and is related to the functional groups, which has to be taken into consideration when looking at experimental data. In the second part, the inelastic contribution to the total current is shown to be quite small and its real importance lies in probing the device geometry. Several molecules are studied for which experimental data is available for comparison. It is demonstrated that the IETS is very sensitive to the molecular conformation, contact geometry and junction width. It is also found that some of the spectral features that appear in experiment cannot be attributed to the molecular device, but to the background contributions, which shows how theory may be used to complement experiment. This part concludes with a study of the temperature dependence of the inelastic transport. This is very important not only from a theoretical point of view, but also for the experiments since it gives experimentalists a sense of which temperature ranges they can operate for measuring IETS.
QC 20100804. Ändrat titeln från: "Understanding Electron Transport Properties in Molecular Devices" 20100804.

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4

Kula, Mathias. "Understanding electron transport properties in molecular electronic devices /". Stockholm : Bioteknologi, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4500.

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5

Levett, Philip Charles. "New electron transport inhibitors". Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357948.

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6

Restivo, Rick A. "Free electron laser weapons and electron beam transport". Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA333358.

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7

Cao, Hui. "Dynamic Effects on Electron Transport in Molecular Electronic Devices". Doctoral thesis, KTH, Teoretisk kemi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12676.

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HTML clipboardIn this thesis, dynamic effects on electron transport in molecular electronic devices are presented. Special attention is paid to the dynamics of atomic motions of bridged molecules, thermal motions of surrounding solvents, and many-body electron correlations in molecular junctions. In the framework of single-body Green’s function, the effect of nuclear motions on electron transport in molecular junctions is introduced on the basis of Born-Oppenheimer approximation. Contributions to electron transport from electron-vibration coupling are investigated from the second derivative of current-voltage characteristics, in which each peak is corresponding to a normal mode of the vibration. The inelastic-tunneling spectrum is thus a useful tool in probing the molecular conformations in molecular junctions. By taking account of the many-body interaction between electrons in the scattering region, both time-independent and time-dependent many-body Green’s function formula based on timedependent density functional theory have been developed, in which the concept of state of the system is used to provide insight into the correlation effect on electron transport in molecular devices. An effective approach that combines molecular dynamics simulations and first principles calculations has also been developed to study the statistical behavior of electron transport in electro-chemically gated molecular junctions. The effect of thermal motions of polar water molecules on electron transport at different temperatures has been found to be closely related to the temperature-dependent dynamical hydrogen bond network.
QC20100630

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8

Bühler-Paschen, Silke. "Electron transport in polymer composites /". [S.l.] : [s.n.], 1995. http://library.epfl.ch/theses/?nr=1365.

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9

Bell, Louise Carol. "Electron transport reactions of denitrification". Thesis, University of Oxford, 1990. https://ora.ox.ac.uk/objects/uuid:9625557a-fe52-4c94-bc1f-a544275df344.

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A study is reported which demonstrates that electron transport to the reductase reactions of denitrification in the bacterium Thiosphaera pantotropha can occur aerobically. Use of dark-type electrodes has demonstrated that the N₂O reductase enzyme of this organism is active under aerobic conditions, and that O₂ and N₂O reduction can occur simultaneously. The reduction of NO₃^- to N₂ gas, even under aerobic conditions, is shown to proceed via NO as an intermediate. It is concluded that the reaction of NO with O₂ must be sufficiently slow that it does not effectively compete with the reduction of NO to N₂O. The ability of T. pantotropha to catalyse aerobic NO₃^- reduction, the first step of the aerobic denitrification process, is shown to correlate with the expression of a NO₃^- reductase enzyme that is located in the periplasm. This periplasmic enzyme is expressed, and is active, under both aerobic and anaerobic conditions. A membrane bound NO₃^- reductase is also expressed, but only under anaerobic conditions, by this organism. This latter reductase resembles the NO₃^- reductase of Paracoccus denitrificans in respect of both its catalytic properties and the inhibition of activity in intact cells under aerobic conditions. Mutants of T. pantotropha that lack the membrane bound NO₃^- reductase, and not only retain but overproduce the periplasmic enzyme, have been obtained via Tn5 mutagenesis. The periplasmic NO₃^- reductase identified in T. pantotropha bears catalytic and structural similarities to an enzyme previously characterised in some strains of Rhodobacter capsulatus. The ability of strains of R. capsulatus to reduce NO to N₂O is reported together with evidence that there is a discrete NO reductase in this organism. The electron transport pathway to NO reductase has been elucidated. The first identification of a denitrifying strain of R. capsulatus is reported.

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10

Emberly, Eldon. "Electron transport in molecular wires". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ51858.pdf.

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11

Ng, Tao-Cheung Timothy. "Electron transport in narrow channels". Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385955.

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12

Hirst, Judy. "Electron transport in redox enzymes". Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364043.

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13

Nandha, Beena. "Regulation of photosynthetic electron transport". Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502263.

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Investigations in this thesis aimed to understand the mechanisms that regulate the photosynthetic electron transport chain in C3 plants and therefore also the significance of cyclic electron flow (CEF). Physiological analysis of Arabidopsis thaliana photosynthetic pgr5 mutant, which had previously been reported to be a CEF mutant, were undertaken. The reduced state of P700 in the light meant that standard assays for P700 and CEF, using P700 absorbance could not be applied. Design and development of flash spectrophotometric techniques were necessary. This primarily involved P700 oxidation kinetics at 820 nm combined with the electrochromic shift at 520 nm to measure electrical field generation.

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14

Wilowska, A. C. "Modelling electron transport in photosynthesis". Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37899.

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15

Nilwala, Gamaralalage Premasiri Kasun Viraj Madusanka. "Electron Transport in Chalcogenide Nanostructures". Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1572259784431038.

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16

Negri, Carlotta. "Controlling electron transport : quantum pumping and single-electron tunneling oscillations". Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14670/document.

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Exploiter des effets dépendants du temps pour induire et contrôler des courants à travers des conducteurs mésoscopiques et nanoscopiques est un enjeu majeur dans le domaine du transport quantique. Dans cette thèse, nous considérons deux systèmes de taille nanométrique pour lesquels un courant est induit grâce au couplage entre champs extérieurs dépendants du temps et le transport d'électrons. Nous étudions d'abord un problème de pompage quantique au sein d'un système à trois sites en configuration d'anneau, en considérant la possibilité d'induire un courant continu par modulation temporelle des paramètres de contrôle. Nous nous intéressons en particulier à la transition entre régime adiabatique et antiadiabatique en présence d'un mécanisme de dissipation modélisé par un couplage entre le système et un bain extérieur.Nous montrons que le modèle dissipatif admet une solution analytique complète valable pour la composante DC du courant à fréquence arbitraire. Ceci nous permet de bien comprendre comment le courant induit dépend de la fréquence de pompage. Nous nous concentrons ensuite sur un autre système de contrôle du courant exploitant le phénomène des oscillations tunnel à un électron (SETOs). Contrairement au cas précédent, ici la circulation d'un courant continu à travers un circuit comportant une jonction tunnel produit, pour le régime approprié, un courant quasi-périodique d'électrons. On étudie le spectre de bruit à température nulle d'une jonction tunnel dans différents environnements résistifs dans le but de déterminer les limites du régime des SETOs et de quantifier leur degré de périodicité. Nous généralisons par la suite les résultats à température finie et discutons des effets des fluctuations quantiques
Exploiting time-dependent effects to induce and control currents through mesoscopic and nano\-scopic conductors is a major challenge in the field of quantum transport. In this dissertation we consider two nanoscale systems in which a current can be induced through intriguing mechanisms of coupling between excitations by external fields and electron transport.We first study a quantum pumping problem, analyzing the possibility to induce a DC response to an AC parametric driving through a three-site system in a ring configuration. We are interested in particular in the crossover between adiabatic and antiadiabatic driving regimes and in the presence of dissipation, which is accounted for by coupling with an external bath. We show that for a clever choice of this coupling the dissipative model admits a full analytical solution for the steady state current valid at arbitrary frequency, which allows us to fully understand the pumping-frequency dependence of the induced current. We then focus on a different current-controlling scheme exploiting the phenomenon of single-electron tunneling oscillations (SETOs). In this case, opposite to what happens for pumping, an AC effect, an almost periodic current of single electrons, arises through a tunnel junction circuit as a consequence of a DC bias. We study the zero-temperature noise spectrum of a tunnel junction in different resistive environments with the aim to determine the boundaries of the SETOs regime and quantify their quality in terms of periodicity. We then discuss the finite-temperature generalization and the possibility to account for the effects of quantum fluctuations

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17

Dasgupta, Subho. "Tuneable electron transport in metallic nanostructures". Eggenstein-Leopoldshafen Forschungszentrum Karlsruhe GmbH, 2009. http://d-nb.info/999765485/34.

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18

Diaconescu, Dorina. "Ballistic electron transport in mesoscopic samples". [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=962295191.

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19

Smedja, Bäcklund Anna. "Electron transport in microbial chlorate respiration". Licentiate thesis, Karlstad University, Faculty of Technology and Science, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-3777.

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Several bacterial species are capable to use perchlorate and/or chlorate as an alternative electron acceptor in absence of oxygen. Microbial respiration of oxochlorates is important for biotreatment of effluent from industries where oxochlorates are produced or handled. One of these species, the Gram-negative Ideonella dechloratans, is able to reduce chlorate but not perchlorate. Two soluble enzymes, chlorate reductase and chlorite dismutase, participate in the conversion of chlorate into chloride and molecular oxygen. The present study deals with the electron transport from the membrane-bound components to the periplasmic chlorate reductase. Soluble c cytochromes were investigated for their ability to serve as electron donors to chlorate reductase. The results show that a 6 kDa c cytochrome serves as electron donor for chlorate reductase. This cytochrome also serves as electron donor for a terminal oxidase in the reduction of oxygen that is produced in the course of chlorate respiration. A gene encoding a soluble c cytochrome was found in close proximity to the gene cluster for chlorate reduction. This gene was cloned and expressed heterologously, and the resulting protein was investigated as a candidate electron donor for chlorate reductase. Electron transfer from this protein could not be demonstrated, suggesting that the gene product does not serve as immediate electron donor for chlorate reductase.

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20

Rossokhaty, Oleksandr. "Non-equilibrium transport in electron solids". Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/60199.

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Electron-electron interactions inside of two dimensional electron gases (2DEG) in out-of-plane magnetic field and at very low temperatures under certain conditions can lead to electron localization in Wigner crystals or even more complex periodic structures. These states are usually referred to as electron solid phases and result in Reentrant Integer Quantum Hall Effect (RIQHE) in transport measurements. However, their microscopic description remains unclear, as insulating phases with different microscopic structure demonstrate indistinguishable macroscopic transport properties. In this work the transport of the electron solids is investigated away from equilibrium conditions. This approach allows to break an insulating state by application of significant current bias to the 2DEG. As bias current increases, longitudinal and Hall resistivities measured for these states show multiple sharp breakdown transitions. Whereas the high bias breakdown of fractional quantum Hall states is consistent with simple heating, the nature of RIQH breakdown remains to be a subject of a considerable debate. A comparison of RIQH breakdown characteristics at multiple voltage probes indicates that these signatures can be ascribed to a phase boundary between broken-down and unbroken regions, spreading chirally from source and drain contacts as a function of bias current and passing voltage probes one by one. It is shown, that the chiral sense of the spreading is not set by the chirality of the edge state itself, instead depending on electron- or hole-like character of the RIQH state. Although at high current bias the electron temperature is unmeasurable with standard techniques, the data shows that electron solid states appear to stay temperature sensitive even after the RIQH effect is destroyed. A comparison of temperature dependence and the spatial distribution of the Hall potential along the edge provides an evidence, that the bulk 2DEG remains insulating up to surprisingly high biases. Finally a metastable stripe phase around $\nu=9/2$ is investigated under non-equilibrium conditions in the sample with electron density, which is close to the stripe reorientation critical point. The anisotropy of non-equilibrium stripe phase under high current biases shows a strong dependence of the natural orientation of stripes on exact filling factor.
Science, Faculty of
Physics and Astronomy, Department of
Graduate

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21

Rolfe, Stephen Alexander. "Electron transport in cyanobacterial photosystem II". Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.258430.

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22

Burrows, P. E. "Electron Transport in Langmuir-Blodgett films". Thesis, Queen Mary, University of London, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531005.

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23

Hoffmann, James A. "Electron transport in interacting quantum wires". Virtual Press, 2003. http://liblink.bsu.edu/uhtbin/catkey/1259758.

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Nanoscale wires and molecules have remarkable electrical properties that make them well suited for new electronic devices. The projected device densities result in very small separation distances and therefore the possibility of device-device interactions. However, we do not know what impacts wire-wire interactions might have on the properties of closely spaced devices. If two quantum wires interact, what types of effects will there be on transport properties such as conductance? How would the coupling strength, length of wire, position of contact, or the energy of the electrons affect conductance? Understanding the effects of the interactions will assist the construction of efficient nanoscale devices.This thesis examined the effects of interaction on the low-field conductance using a simple classical model and two quantum models of coupled quantum wires fabricated electrostatically in the two-dimensional electron gas at the interface of the heterostructure A1GaAs/GaAs. We considered the effect of position and length of an interaction between two parallel quantum wires formed by hard wall boundaries and connected to electron reservoirs. Our second model consisted of two artificial molecular wires, i.e., parallel chains of quantum dots. We used a one-electron Schrodinger equation in the envelope approximation, a tight-binding Hamiltonian, and a recursive Green's function method to study the electron transport properties. Multi-parameter computations using a fortran-95 computer model provided data for an analysis of the relationships among conductance, the interaction strength, interaction location, and electron energy.In contrast to the monotonic changes predicted by the classical model, the lowfield conductance of interacting hard wall quantum wires varies in an oscillatory manner with the perturbing interaction strength and position. For electron energies below the first conductance plateau, Breit-Wigner resonances appear as a consequence of coupling. These conductance properties are explained with reference to quasi-bound states created by reflections at the end boundaries of the wires and the separating wall.At low electron energies, the conductance signature of a symmetric artificial molecule composed of serial quantum dots is a band of resonances. Coupled artificial molecular wires display a split-off molecular band with an energy separation that grows with the coupling strength and a bandwidth that narrows. The position of the Fermi energy relative to the molecular band states plays a dominant role in determining the lowfield conductance of interacting artificial molecules. The conductance variation with coupling ranges from oscillatory to monotonic, depending on the Fermi energy. Varying the atom-atom coupling position in the molecular wires causes a relatively small shift in the resonance band energies.
Department of Physics and Astronomy

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24

Bailey, Steven W. D. "Single electron transport in carbon nanotubes". Thesis, Lancaster University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289056.

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25

Mavroidis, Constantinos. "Electron transport in GaN epitaxial layers". Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407135.

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26

McFadden, C. "Electron transport in GaAs semiconductor devices". Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332168.

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27

Yan, C. "Electron transport in integrated quantum systems". Thesis, University College London (University of London), 2016. http://discovery.ucl.ac.uk/1531982/.

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In this thesis, integrated quantum devices defined using a split gate technique are studied experimentally. These integrated devices provide a novel platform to investigate the property of quantum systems, such as spin polarization, via non-local measurement. Information extracted from these integrated devices leads to a comprehensive understanding of the puzzling phenomenon such as the 0.7 anomaly. Meanwhile, these devices are possibly suitable for studying quantum entanglement because perturbation due to measurement is minimized in the non-local setup. Devices demonstrated here are also promising to be used as a building block such as quantum injector/detector or quantum bus (which is a information channel where quantum information can be transported coherently) for more complicated quantum systems. In the first experiment, a transverse electron focusing in n-type GaAs heterojunction is present where pronounced splitting of odd focusing peaks are observed. From the asymmetry of sub-peaks of the first focusing spin polarization is extracted directly, this provides direct evidence for intrinsic spin polarization in a quasi-one-dimensional system. Parameters which may affect transverse electron focusing are studied systemically. Changing the shape of the injector, thus tuning the adiabaticity of the injection process, can influence the presence of peak splitting or not, with the sharp (non-adiabatic) injector the peak splitting is absent while peak splitting is observed with the flat (adiabatic) injector. Adjusting the length of injector affects the spin polarization, the longer the channel the higher the spin polarization can be achieved. This highlights the role of exchange interaction which results in the spin polarization in the quasi-1D channel. Applying a dc source-drain bias leads to such a result, peak splitting is preserved with negative bias while it smears out with positive bias when the bias is above a particular value (0.5 mV in the experiment), this proves the existence of spin-gap. In the second experiment, the coupling between different quantum devices are investigated by using an integrated quantum device consisting of an QPC and electronic cavity, where the cavity is defined with the arc-shaped gate and an inclined reflector. Unique features such as the double-peak structure occurs in the 1D-2D transition regime of the arc-QPC and 5 fine oscillations associated with conductance plateaus and 0.7 anomaly are observed when the reflector voltage is sufficiently negative and these features smear out when the reflector voltage is less negative. The double-peak structure and fine oscillations are proved to arise from the coupling between the discrete states in the QPC and continuum cavity state by the manifestation of Fano resonance via tuning reflector voltage or small transverse magnetic field. In the third experiment, quantum interference in a double-cavity system is studied by magneoresistance measurement. An unique evolution of the line shape of the magnetoresistance are observed, the magnetoresistance has a Lorentzian shape, corresponding to ergodic and chaotic motion, when the injector conductance is sufficiently small and then alters into linear line shape arising from non-ergodic and regular motion when injector is opens a bit more and finally a Lorentzian shape when the injector opens even further. Apart from the line shape, the strength of the magnetoresistance is found to fluctuate with injector conductance, it is enhanced at conductance plateaus and weakens elsewhere. Such behaviours are likely to arise from both deformation of the arc-shaped potential barrier at the vicinity of injector and detector QPC as well as the non-uniform spatial distribution of the cavity state.

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28

Bandurin, Denis. "Electron transport in atomically thin crystals". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/electron-transport-in-atomically-thin-crystals(e184d9d8-ad44-41e0-8be9-bd381d6a21d6).html.

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This work is dedicated to electron transport in atomically thin crystals. We explore hydrodynamic effects in the electron liquid of graphene and perform a comprehensive study of electronic and optical properties of a novel 2D semiconductor - indium selenide(InSe). Graphene hosts a high quality electron system with weak phonon coupling such that electron-electron scattering can be the dominant process responsible for the establishment of local equilibrium of the electronic system above liquid nitrogen temperatures. Under these conditions, charge carriers are expected to behave as a viscous fluid with a hydrodynamic behaviour similar to classical gases or liquids. In this thesis, we aimed to reveal this hydrodynamic behaviour of the electron fluid by studying transport properties of high-quality graphene devices. To amplify the hydrodynamic effects, we used a special measurement geometry in which the current was injected into the graphene channel and the voltage was measured at the contact nearest to the injector. In this geometry we detected a negative signal which is developed as a result of the viscous drag between adjacent fluid layers, accompanied by the formation of current vortices. The magnitude of the signal allowed us to perform the first measurement of electron viscosity. In order to understand how an electron liquid enters the hydrodynamic regime we studied electron transport in graphene point contacts. We observed a drop in the point contact resistance upon increasing temperature. This drop was attributed to the interaction-induced lubrication of the point contact boundaries that was found to be strong enough to prevent momentum relaxation of charge carriers. The viscosity of the electron fluid was measured over a wide range of temperatures and at different carrier densities. Experimental data was found to be in good agreement with many-body calculations. In this work we also studied transport properties of two-dimensional InSe. We observed high electron mobility transport, quantum oscillations and a fully developed quantum Hall effect. In optical studies, we revealed that due to the crystal symmetry a monolayer InSe features suppressed recombination of electron-hole pairs.

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29

Pettersen, Eirik. "Electron transport in gated undoped heterostructures". Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627583.

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30

Smedja, Bäcklund Anna. "Electron transport in microbial chlorate respiration /". Karlstad : Faculty of Technology and Science, Chemistry, Karlstads University, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-3777.

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31

Shao, Fangwei Dougherty Dennis A. "DNA-mediated hole and electron transport /". Diss., Pasadena, Calif. : California Institute of Technology, 2008. http://resolver.caltech.edu/CaltechETD:etd-06282007-105808.

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32

Na, Kyungsun. "Quantum transport in an electron waveguide /". Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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33

Purbach, Ulrich. "Electron transport in mesoscopic metallic structures /". Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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34

Scannell, William Christian 1970. "Chaotic electron transport in semiconductor devices". Thesis, University of Oregon, 2010. http://hdl.handle.net/1794/10933.

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xix, 171 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.
The field of quantum chaos investigates the quantum mechanical behavior of classically chaotic systems. This dissertation begins by describing an experiment conducted on an apparatus constructed to represent a three dimensional analog of a classically chaotic system. Patterns of reflected light are shown to produce fractals, and the behavior of the fractal dimension D F is shown to depend on the light's ability to escape the apparatus. The classically chaotic system is then used to investigate the conductance properties of semiconductor heterostructures engineered to produce a conducting plane relatively free of impurities and defects. Introducing walls that inhibit conduction to partition off sections considerably smaller than the mean distance between impurities defines devices called 'billiards'. Cooling to low temperatures enables the electrons traveling through the billiard to maintain quantum mechanical phase. Exposure to a changing electric or magnetic field alters the electron's phase, leading to fluctuations in the conductance through the billiard. Magnetoconductance fluctuations in billiards have previously been shown to be fractal. This behavior has been charted using an empirical parameter, Q , that is a measure of the resolution of the energy levels within the billiard. The relationship with Q is shown to extend beyond the ballistic regime into the 'quasi-ballistic' and 'diffusive' regimes, characterized by having defects within the conduction plane. A model analogous to the classically chaotic system is proposed as the origin of the fractal conductance fluctuations. This model is shown to be consistent with experiment and to account for changes of fine scale features in MCF known to occur when a billiard is brought to room temperature between low temperature measurements. An experiment is conducted in which fractal conductance fluctuations (FCF) are produced by exposing a billiard to a changing electric field. Comparison of D F values of FCF produced by electric fields is made to FCF produced by magnetic fields. FCF with high D F values are shown to de-correlate at smaller increments of field than the FCF with lower D F values. This indicates that FCF may be used as a novel sensor of external fields, so the response of FCF to high bias voltages is investigated.
Adviser: Stephen Kevan, Chairperson, Physics; Richard Taylor, Advisor, Physics; Robert Zimmerman, Member, Physics; Stephen Gregory, Member, Physics; David Johnson, Outside Member, Chemistry

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35

Schwab, Peter [Verfasser]. "Electron-Electron Interactions and Charge Transport in Mesoscopic Conductors / Peter Schwab". Augsburg : Universität Augsburg, 2007. http://d-nb.info/1077692536/34.

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36

Jansen, Richard-Jan Engel. "Electron transport and scattering in the 2DEG base hot-electron transistor". Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389876.

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37

Kumar, Arvind Shankar Shankar. "Investigating Electron-Electron Interactions in 2D Semiconductor Systems through Quantum Transport". Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1624475904980951.

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38

Bao, Yunjuan. "Theoretical study of spin transport in low-dimensional systems". Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B40687570.

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39

Arabshahi, Hadi. "Simulations of electron transport in GaN devices". Thesis, Durham University, 2002. http://etheses.dur.ac.uk/4119/.

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This thesis deals with the development and application of Monte Carlo simulations to study electron transport in bulk GaN in the wurtzite crystal structure and the properties of field effect transistors made from the material. There is a particular emphasis on transport in the high electric field regime and transistors operating at high voltages. The simulation model includes five sets of non-parabolic conduction band valleys which can be occupied by electrons during high field transport. The effects on electron transport of impurities and the relevant phonon scattering mechanisms have been considered. Results for electron transport at both low and high electric field are presented and compared with the properties of GaN in the zincblende structure, of other group-III nitride semiconductors, and of GaAs. The dependence of the transport properties on the material parameters is discussed and also with regard to the temperature, donor concentration and electric field magnitude and direction. The transport properties of electrons in wurtzite GaN n+-i(n)-n+ diodes are also explored, including the effect of the upper valleys and the temperature on hot electron transport. Simulations have also been carried out to model the steady-state and transient properties of GaN MESFETs that have recently been the subject of experimental study. It has been suggested that traps have a substantial effect on the performance of GaN field effect transistors and we have developed a model of a device with traps to investigate this suggestion. The model includes the simulation of the capture and release of electrons by traps whose charge has a direct effect on the current flowing through the transistor terminals. The influence of temperature and light on the occupancy of the traps and the /- V characteristics are considered. It is concluded that traps are likely to play a substantial role in the behaviour of GaN field effect transistors. Further simulations were performed to model electron transport in AlGaN/GaN hetero-junction FETs. So called HFET structures with a 78 nm Alo.2Gao.8N pseudomorphically strained layer have been simulated, with the inclusion of spontaneous and piezoelectric polarization effects in the strained layer. The polarization effects are shown to not only increase the current density, but also improve the electron transport by inducing a higher electron density close to the positive charge sheet that occurs in the channel.

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40

Kaufman, David Kaufman David. "Electron transport in V-groove quantum wires /". [S.l.] : [s.n.], 2000. http://library.epfl.ch/theses/?nr=2239.

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41

Li, Hui. "Control and transport of intense electron beams". College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1772.

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Thesis (Ph. D.) -- University of Maryland, College Park, 2004.
Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

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42

Sanchez, Lotero Adriana Mercedes. "Thermal transport in strongly correlated electron systems". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1121946609637-03206.

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43

Hammer, Jan [Verfasser]. "Coherent electron transport in nanostructures / Jan Hammer". Konstanz : Bibliothek der Universität Konstanz, 2010. http://d-nb.info/1017326541/34.

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44

Edgren, Tomas. "Electron transport to nitrogenase in Rhodospirillum rubrum /". Stockholm : Dept. of Biochemistry and Biophysics, Stockholm university, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-874.

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45

Cheekoori, Reddiprasad. "Electron transport in wide energy gap semiconductors". Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/40421.

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Abstract (sommario):

The dependence of the low-field electron drift mobility on the crystal temperature is determined for a number of wide energy gap semiconductors of interest. The materials considered include gallium nitride, aluminium nitride, indium nitride, and zinc oxide; while indium nitride is not a wide energy gap semiconductor in of itself, alloys of indium nitride with gallium nitride are. For the bulk results, it is found that indium nitride exhibits the highest low-field electron drift mobility while aluminium nitride exhibits the lowest low-field electron drift mobility. This is related to the small effective mass of electrons in indium nitride and the large effective mass of electrons in aluminium nitride. For the case of electrons confined within a two-dimensional electron gas, it is found that the low-field electron drift mobility exceeds that corresponding to the bulk material. This is due to the enhanced screening that electron concentrations exceeding the bulk ionized impurity concentrations level offer, i.e., surplus electrons act to further screen the ionized impurities; in a two-dimensional electron gas, the electron concentrations may far exceed those found in a bulk material. Recommendations for further study are suggested.

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46

Schneider, Adam. "Coherent electron transport in triple quantum dots". Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32541.

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We use a quantum master equation approach to study the transport properties of a triple quantum dot ring. Unlike double quantum dots and triple quantum dot chains, this geometry gives two transport paths with a relative phase sensitive to magnetic ﬂux via the Aharonov-Bohm effect. This gives rise to a coherent population trapping effect and what is known as a "dark state". Unlike other master equation techniques valid only in the high bias voltage limit, our treatment reproduces such results as well as giving an analytic zero-bias conductance formula. As well as providing a more robust signature of this "dark state" physics, our model further predicts a negative differential resistance in connection with high bias rectiﬁcation already predicted.
Nous utilisons une approche d´equation quantique maîtresse pour étudier les propriétés de transport des points quantiques triples en forme d'anneau. Contrairement aux points quantiques doubles et triples en forme de chaînes, cette géométrie offre deux chemins pour le transport avec une phase quantique relative qui est sensible au ﬂux magnétique en raison de l'effet Aharonov-Bohm. Ceci méne à un effet de piégeage de population cohérent et cela est connu sous le nom d'un "état sombre". Contrairement à d'autres techniques d'équation maîtresse qui sont seulement valides dans la limite d'un potentiel électrique élevé, notre méthode reproduit les résultats de ces derniers en plus de donner une expression analytique pour la conductance différentielle de zéro potentiel électrique. En plus de donner une optique plus robuste de la physique "d´etats sombres", notre modèle prédit une résistance différentielle négative qui est reliée au phénomène déjà prédit de rectiﬁcation à potentiel élevé.

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47

Paquin, Normand. "Electron transport in uniaxially stressed silicon MOSFETs". Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257213.

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48

Berks, Benjamin Charles. "Molecular characterisation of bacterial electron transport proteins". Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302884.

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49

Gauden, David Edwards. "Electron transport dependent taxis in Rhodobacter sphaeroides". Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320586.

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50

Hess, Robert. "Electron transport modelling in X-ray tubes". Thesis, University of Surrey, 1997. http://epubs.surrey.ac.uk/970/.

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