Dissertations / Theses on the topic 'Surface properties of condensed matter'
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Caramella, Lucia. "Theoretical spectroscopy of realistic condensed matter systems." Paris 6, 2009. http://www.theses.fr/2009PA066019.
Full textDiLisi, Gregory Anthony. "Oligomeric liquid crystals: Viscoelastic properties and surface interactions." Case Western Reserve University School of Graduate Studies / OhioLINK, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=case1060023040.
Full textDelage, Patrick. "Growth mode and frictional properties of ultrathin films of sodium chloride on copper surfaces." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84022.
Full textHaider, Muhammad Baseer. "Surface and Bulk Properties of Magnetically Doped GaN and Their Dependence on the Growth Conditions." Ohio University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1132011994.
Full textPatra, Abhirup. "Surface properties, adsorption, and phase transitions with a dispersion-corrected density functional." Diss., Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/516784.
Full textPh.D.
Understanding the “incomprehensible” world of materials is the biggest challenge to the materials science community. To access the properties of the materials and to utilize them for positive changes in the world are of great interest. Often scientists use approximate theories to get legitimate answers to the problems. Density functional theory (DFT) has emerged as one of the successful and powerful predictive methods in this regard. The accuracy of DFT relies on the approximate form of the exchange-correlation (EXC) functional. The most complicated form of this functional can be as accurate as more complicated and computationally robust method like Quantum Monte Carlo (QMC), Random Phase Approximation (RPA). Two newest meta-GGAs, SCAN and SCAN+rVV10 are among those functionals. Instantaneous charge fluctuation between any two objects gives rise to the van der Waals (vdW) interactions (often termed as dispersion interactions). It is a purely correlation effect of the interacting electrons and thus non-local in nature. Despite its small magnitude it plays a very important role in many systems such as weakly bound rare-gas dimers, molecular crystals, and molecule-surface interaction. The traditional semi-local functionals can not describe the non-local of vdW interactions; only short- and intermediate-range of the vdW are accounted for in these functionals. In this thesis we investigate the effect of the weak vdW interactions in surface properties, rare-gas dimers and how it can be captured seamlessly within the semi-local density functional approximation. We have used summed-up vdW series within the spherical-shell approximation to develop a new vdW correction to the meta-GGA-MS2 functional. This method has been utilized to calculate binding energy and equilibrium binding distance of different homo- and hetero-dimers and we found that this method systematically improves the MGGA-MS2 results with a very good agreement with the experimental data. The binding energy curves are plotted using this MGGA-MS2, MGGA-MS2-vdW and two other popular vdW-corrected functionals PBE-D2, vdW-DF2. From these plots it is clear that our summed-up vdW series captures the long-range part of the binding energy curve via C6, C8, and, C10 coefficients. The clean metallic surface properties such as surface energy, work functions are important and often play a crucial role in many catalytic reactions. The weak dispersion interactions present between the surfaces has significant effect on these properties. We used LDA, PBE, PBSEsol, SCAN and SCAN+rVV10 to compute the clean metallic surface properties. The SCAN+rVV10 seamlessly captures different ranges of the vdW interactions at the surface and predicts very accurate values of surface energy ( ) , and work function (𝞥) and inter-layer relaxations (𝞭%). Our conclusion is adding non-local vdW correction to a good semi-local density functional such as SCAN is necessary in order to predict the weak attractive vdW forces at the metallic surface. The SCAN+rVV10 has also been employed to study the hydrogen evolution reaction (HER) on 1T-MoS2. We have chosen as a descriptor differential Gibbs free energy (𝚫 GH ) to understand the underlying mechanism of this catalytic reaction. Density functional theory calculations agree with the experimental findings. In the case of layered materials like 1T-MoS2, vdW interactions play an important role in hydrogen binding, that SCAN+rVV10 calculation was able to describe precisely. We have also used SCAN and SCAN+rVV10 functionals to understand bonding of CO on (111) metal surfaces, where many approximations to DFT fail to predict correct adsorption site and adsorption energy. In this case SCAN and SCAN+rVV10 do not show systematic improvements compared to LDA or PBE, rather, both SCAN and SCAN+rVV10 overbind CO more compared to PBE but less compared to the LDA. This overbinding of CO is associated with the incorrect charge transfer from metal to molecule and presumably comes from the density-driven self-interaction error of the functionals. In this thesis we assessed different semi-local functionals to investigate molecule surface systems of 𝞹-conjugated molecules (thiophene, pyridine) adsorbed on Cu(111), Cu(110), Cu(100) surfaces. We find the binding mechanism of these molecules on the metallic surface is mediated by short and intermediate range vdW interactions. Calculated values of binding energies and adsorbed geometries imply that this kind of adsorption falls in the weak chemisorption regime. Structural phase transitions due to applied pressure are very important in materials science. However, pressure induced structural phase transition in early lanthanide elements such as Ce are considered as abnormal first order phase transition. The Ce 𝝰-to-𝝲 isostructural phase transition is one of them. The volume collapse and change of magnetic properties associated with this transition are mediated by the localized f-electron. Semi-local density functionals like LDA, GGA delocalize this f-electron due to the inherent self-interaction error (SIE) of these functionals. We have tested the SCAN functional for this particular problem, and, it was found that the spin-orbit coupling calculations with SCAN not only predicts the correct magnetic ordering of the two phases, but also gives a correct minima for the high-pressure 𝝰-Ce phase and a shoulder for the low-pressure 𝝲-Ce phase.
Temple University--Theses
Torrance, David Britt. "Growth and electronic properties of nanostructured epitaxial graphene on silicon carbide." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50205.
Full textPer request of the author and the advisor, and with the approval of the graduate office, the Acknowledgements page was replaced with an errata.
Alcantara, Ortigoza Marisol. "Theoretical studies of electronic, vibrational, and magnetic properties of chemisorbed surfaces and nanoalloys." Diss., Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/496.
Full textRegoutz, Anna. "Structural and electronic properties of metal oxides." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:6f425890-b211-4b35-b438-b8de18f7ae64.
Full textBekele, Selemon. "Structural and Dynamical Properties of Water and Polymers at Surfaces and Interfaces: A Molecular Dynamics Investigation." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1530040420616781.
Full textBidermane, Ieva. "Structure and Electronic Properties of Phthalocyanine Films on Metal and Semiconductor Substrates." Doctoral thesis, Uppsala universitet, Molekyl- och kondenserade materiens fysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-217086.
Full textSeel, Jennifer A. "Ion-surface scattering measurements of the (110) surface of titanium dioxide." Thesis, University of Ottawa (Canada), 1997. http://hdl.handle.net/10393/4149.
Full textBulicz, John. "Single crystal surface investigations using RHEED." Thesis, University of Ottawa (Canada), 1992. http://hdl.handle.net/10393/7501.
Full textZhang, Chang-Hua. "Stability and surface dynamics of metal nanowires." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/290097.
Full textMeng, Xiadong. "Surface magneto-optic Kerr effect of NiCoCu multilayers." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22775.
Full textSMOKE measurements on a series of sputtered $ rm Ni sb{80}Co sb{20}15 A$/CU$(t sb{Cu}),$ where $t sb{Cu}$ is the thickness of Cu spacer layer, multilayers confirms that the coupling strength in these multilayers oscillates from antiferromagnetic (AF) coupling to ferromagnetic coupling as a function of Cu spacer layer thickness. Low-angle x-ray diffraction and SMOKE measurements on a series of AF-coupled $ rm (Ni sb{80}Co sb{20}15 A$/Cu20A) $ times$ N multilayers with bilayer numbers N ranging from 8 to 100 shows that cumulative interface roughness increases with increasing N, as do the saturation field and coercivity. This is possibly due to the out-of-plane anisotropy associated with cumulative interface roughness in multilayers.
An AF-coupled $ rm (Ni sb{70}Co sb{30}15 A$/Cu20A) $ times$ 10 was continually annealed up to 400$ sp circ$C in several steps, and the magnetic behaviour of the sample was evaluated as a function of annealing temperatures. $ rm (Ni sb{70}Co sb{30}15 A$/CU20A/Ni$ rm sb{70}Co sb{30} A$/CU20A) $ times$ 5 multilayer was used for investigating the AF coupling between magnetic layers of unequal thicknesses. Finally, an AF-coupled $ rm (Ni sb{70}Co sb{30}15 A$/Cu20A/Ni$ rm sb{70}Co sb{30}15 A$/Cu35A) $ times$ 5 multilayer was sputtered and used to study the magnetization of an AF-coupled multilayer with two different coupling strengthes.
Tabard-Cossa, Vincent. "Microcantilever actuation generated by redox-induced surface stress." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102214.
Full textThe objective of the present study is to gain a better understanding of the mechanisms responsible for the nanomechanical motion of cantilever sensors during adsorption and absorption processes. The study of these simple model systems will lead to a general understanding of the cantilever-based sensor's response and provide insights into the physical origin of the measured surface stress.
The surface stress generated by the electrochemically-controlled absorption of ions into a thin polypyrrole film is investigated. A compressive change in surface stress of about -2 N/m is measured when the polymer is electrochemically switched between its oxidized and neutral (swollen) state. The volume change of the polymer phase with respect to the gold-coated cantilever is shown to be responsible for the mechanical motion observed.
The potential-induced surface stress and surface energy change on an Au(111)-textured cantilever, in a 0.1 M HClO4 electrolyte, are simultaneously measured. These measurements revealed that for solid electrodes these two thermodynamic parameters are significantly different. In the double layer region, a surface stress change of -0.55 +/-0.06 N/m is measured during ClO4- adsorption whereas the surface energy variation is smaller by one order of magnitude. The origin of the surface stress change at the metal-electrolyte interface is understood by the variation in electron density at the surface which alters the inter-atomic bonds strength between surface atoms, while the specificity of adsorption of ions is found to be mostly responsible for the fine structure of the surface stress profile.
Rost, A. W. "Magnetothermal properties near quantum criticality in the itinerant metamagnet Sr₃Ru₂O₇ /." St Andrews, 2009. http://hdl.handle.net/10023/837.
Full textRaymond, Sylvain. "Zero-dimensional properties of self-assembled islands." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ28370.pdf.
Full textLee, Dok Won. "Structural and magnetic properties of copperiron multilayers." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20264.
Full textThe magnetic transition from ferromagnetism to paramagnetism with decreasing tFe was confirmed by conversion-electron Mossbauer spectroscopy (CEMS), vibrating sample magnetometry, and magnetotransport measurements. The monotonic decrease in the average hyperfine field with t Fe indicates that the transition is a gradual process as t Fe decreases from 34 A down to 7 A. The isomer shift of the singlets in the CEM spectra suggests the presence of fcc Fe, while the observed doublet is assigned to the Cu-Fe alloy phase at the interfaces.
The variation of magnetoresistance (MR) with t Cu indicates that for a nominal t Fe of 20 A the multilayer has a well-defined superlattice structure, whereas multilayers with nominal tFe, of 5 A have a granular-alloy-like structure. AC susceptometry provided direct evidence for island formation for nominal tFe = 5 A by exhibiting the blocking characteristics of superparamagnets. The temperature-dependence of the magnetization suggests that for nominal tFe = 5 A, 75% of the Fe atoms are in the superparamagnetic bcc phase, leaving the remaining 25% in the Cu-Fe alloy and fcc Fe phases.
The observed magnetic transition is likely due to superparamagnetic relaxation rather than a structural transition from bcc Fe to fcc Fe as t Fe decreases below a critical thickness tC at which a multilayer structure becomes an island structure.
Triola, Christopher Lawrence Charles. "Electronic properties of chiral two-dimensional materials." W&M ScholarWorks, 2015. https://scholarworks.wm.edu/etd/1539624004.
Full textGodin, Michel. "Surface stress, kinetics, and structure of alkanethiol self-assembled monolayers." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85551.
Full textThese measurements were performed in order to gain insight into the mechanisms involved in the self-assembly process and into the origins of the associated surface stress. Moreover, these studies were used to characterize and optimize the response of cantilever-based sensors based on functionalized SAM technology in terms of reliability, sensitivity, and reproducibility.
The evolution of the surface stress induced during alkanethiol SAM formation reveals features associated with coverage-dependent structural phase transitions. These results show that both the kinetics of SAM formation and the resulting SAM structure are strongly influenced by the surface structure of the underlying gold substrate, by the impingement rate of the alkanethiol molecules onto the gold surface, and by the cleanliness of the gold surface. In particular, it was found that a minimum gold grain size is necessary in order for the SAM to achieve the standing-up phase, for which large compressive surface stresses (~10 N/m) are measured. In addition, these results show that alkanethiol SAMs can become kinetically trapped in metastable intermediate states (lying-down phase) for formation on small-grained gold surfaces and/or at low alkanethiol vapor concentrations. Theoretical modeling of the origins of the induced surface stress reveals that inter-molecular Lennard-Jones interactions and electrostatic repulsion between adsorbed species play minimal roles in the development of the surface stress. Changes in the electronic structure of the underlying gold substrate are more likely to account for the large compressive surface stresses observed during alkanethiol SAM formation.
Finnie, Paul D. "The fabrication and optical properties of quantum wires." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq26116.pdf.
Full textKou, Angela. "Microscopic Properties of the Fractional Quantum Hall Effect." Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:11161.
Full textPhysics
Helbers, Andrew J. "Magneto-Optical Properties of Rare-Earth Doped Semiconductors." Thesis, Lehigh University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10623187.
Full text
Brackstone, Mark Andrew. "Dynamic properties of models of modulated systems in condensed matter." Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.255764.
Full textCamarÃo, Diego de Lucena. "Diffusive properties of soft condensed matter systems under external confinement." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13612.
Full textNesta tese estudamos a influÃncia de potenciais de confinamento externos nas propriedades dinÃmicas de sistemas de matÃria condensada mole. Analisamos as propriedades difusivas de dois sistemas especÃficos utilizando simulaÃÃes computacionais (DinÃmica Molecular de Langevin e DinÃmica Browniana). No CapÃtulo 1, introduzimos o tÃpico sobre matÃria condensada mole. Mostramos vÃrios aspectos teÃricos e experimentais neste tipo de sistema. Fazemos uma breve introduÃÃo ao tÃpico de difusÃo, onde discutimos os principais aspectos do movimento Browniano. Introduzimos o problema de difusÃo em linha (SFD, do inglÃs "single-file diffusion") e o discutimos, teorica e experimentalmente, no contexto de sistemas de matÃria condensada mole. No CapÃtulo 2, introduzimos os mÃtodos computacionais utilizados nesta tese. Discutimos os mÃtodos de DinÃmica Molecular e suas variantes, o mÃtodo de DinÃmica de Langevin e DinÃmica Browniana. TambÃm introduzimos algoritmos de integraÃÃo utilizados nos capÃtulos posteriores. Nos Caps. 3, 4 e 5, analisamos dois sistemas distintos, (i) um sistema de partÃculas de Yukawa confinadas em um canal parabÃlico quasi-unidimensional (q1D) e (ii) um sistema de colÃides magnÃticos sob a influÃncia de um potencial parabÃlico e uma modulaÃÃo periÃdica externa ao longo da direÃÃo nÃo confinada. No primeiro sistema, estudamos a transiÃÃo do regime de difusÃo em linha (SFD) para o regime de difusÃo normal (2D). No segundo sistema, estudamos os efeitos de vÃrios parÃmetros que caracterizam o sistema (e.g., a magnitude do campo magnÃtico externo e a presenÃa da modulaÃÃo periÃdica externa) em suas propriedades dinÃmicas. Finalmente, apresentamos um sumÃrio dos principais resultados obtidos nesta tese e mostramos algumas questÃes em aberto como perspectivas para pesquisas futuras na Ãrea de difusÃo em sistemas de matÃria condensada mole.
In this thesis we study the influence of external confinement potentials on the dynamical properties of soft condensed matter systems. We analyze the diffusive properties of two specific systems by means of Langevin and Brownian Dynamics simulations. In Chapter 1, we introduce the subject of soft condensed matter. We show several theoretical and experimental aspects of these type of systems. We make a brief introduction to the topic of diffusion, where we discuss main aspects of Brownian motion. We introduce the single-file diffusion (SFD) problem and discuss it in the context of soft condensed matter systems, both theoretically and experimentally. In Chapter 2, we introduce the computational method used in this thesis. We discuss Molecular Dynamics (MD) and its variants, Langevin and Brownian Dynamics simulations. We also introduce numerical algorithms used in the following chapters. In Chapters 3, 4 and 5, we analyze two different systems, namely (i) a system of interacting Yukawa particles confined in a parabolic quasi-one-dimensional (q1D) channel and (ii) a system of magnetic colloidal particles under the influence of both a parabolic confinement potential and a periodic external modulation along the unconfined direction. In the former, we study the transition from the single-file diffusion (SFD) regime to the two-dimensional (2D) diffusion regime. In the latter, we study the influence of several parameters that characterizes the system, e.g., the strength of an external magnetic field and the periodic modulation along the unconfined direction, on its dynamical properties. Finally, we present the summary of the main findings reported in this thesis and we show some open questions as perspectives for future research in the field of diffusion in soft condensed matter systems.
Camarão, Diego de Lucena. "Diffusive properties of soft condensed matter systems under external confinement." reponame:Repositório Institucional da UFC, 2014. http://www.repositorio.ufc.br/handle/riufc/11285.
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In this thesis we study the influence of external confinement potentials on the dynamical properties of soft condensed matter systems. We analyze the diffusive properties of two specific systems by means of Langevin and Brownian Dynamics simulations. In Chapter 1, we introduce the subject of soft condensed matter. We show several theoretical and experimental aspects of these type of systems. We make a brief introduction to the topic of diffusion, where we discuss main aspects of Brownian motion. We introduce the single-file diffusion (SFD) problem and discuss it in the context of soft condensed matter systems, both theoretically and experimentally. In Chapter 2, we introduce the computational method used in this thesis. We discuss Molecular Dynamics (MD) and its variants, Langevin and Brownian Dynamics simulations. We also introduce numerical algorithms used in the following chapters. In Chapters 3, 4 and 5, we analyze two different systems, namely (i) a system of interacting Yukawa particles confined in a parabolic quasi-one-dimensional (q1D) channel and (ii) a system of magnetic colloidal particles under the influence of both a parabolic confinement potential and a periodic external modulation along the unconfined direction. In the former, we study the transition from the single-file diffusion (SFD) regime to the two-dimensional (2D) diffusion regime. In the latter, we study the influence of several parameters that characterizes the system, e.g., the strength of an external magnetic field and the periodic modulation along the unconfined direction, on its dynamical properties. Finally, we present the summary of the main findings reported in this thesis and we show some open questions as perspectives for future research in the field of diffusion in soft condensed matter systems.
Nesta tese estudamos a influência de potenciais de confinamento externos nas propriedades dinâmicas de sistemas de matéria condensada mole. Analisamos as propriedades difusivas de dois sistemas específicos utilizando simulações computacionais (Dinâmica Molecular de Langevin e Dinâmica Browniana). No Capítulo 1, introduzimos o tópico sobre matéria condensada mole. Mostramos vários aspectos teóricos e experimentais neste tipo de sistema. Fazemos uma breve introdução ao tópico de difusão, onde discutimos os principais aspectos do movimento Browniano. Introduzimos o problema de difusão em linha (SFD, do inglês "single-file diffusion") e o discutimos, teorica e experimentalmente, no contexto de sistemas de matéria condensada mole. No Capítulo 2, introduzimos os métodos computacionais utilizados nesta tese. Discutimos os métodos de Dinâmica Molecular e suas variantes, o método de Dinâmica de Langevin e Dinâmica Browniana. Também introduzimos algoritmos de integração utilizados nos capítulos posteriores. Nos Caps. 3, 4 e 5, analisamos dois sistemas distintos, (i) um sistema de partículas de Yukawa confinadas em um canal parabólico quasi-unidimensional (q1D) e (ii) um sistema de colóides magnéticos sob a influência de um potencial parabólico e uma modulação periódica externa ao longo da direção não confinada. No primeiro sistema, estudamos a transição do regime de difusão em linha (SFD) para o regime de difusão normal (2D). No segundo sistema, estudamos os efeitos de vários parâmetros que caracterizam o sistema (e.g., a magnitude do campo magnético externo e a presença da modulação periódica externa) em suas propriedades dinâmicas. Finalmente, apresentamos um sumário dos principais resultados obtidos nesta tese e mostramos algumas questões em aberto como perspectivas para pesquisas futuras na área de difusão em sistemas de matéria condensada mole.
Broussell, Isabelle. "Optical properties of alpha-zinc aluminum sulfide:chromium single crystals." Thesis, University of Ottawa (Canada), 1998. http://hdl.handle.net/10393/4514.
Full textWincheski, Russell A. "Characterization of the physical properties of iron polyimide nanocomposites." W&M ScholarWorks, 1999. https://scholarworks.wm.edu/etd/1539623960.
Full textChurch, Christopher J. "The structural, thermal, and magnetic properties of manganese silicon sulfide." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6806.
Full textVachon, Martin. "Optical properties of single quantum dots in high magnetic field." Thesis, University of Ottawa (Canada), 2008. http://hdl.handle.net/10393/28029.
Full textSabet-Sharghi, Riaz. "Composition dependence of mechanical properties in Al-rich metallic glasses." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=26134.
Full textPomorski, Pawel. "Theoretical study of conductance, capacitance and transport properties of nanostructures." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84414.
Full textIn this thesis, we theoretically investigated the conductance and capacitance of mesoscopic and molecular scale systems. Our approach incorporated Landauer-Buttiker transport theory.
We developed a highly efficient method, based on the solution of the time-dependent Schrodinger equation incorporating a magnetic field, to solve the quantum scattering problem in mesoscopic nanostructures. We studied linear response capacitance in a two plate mesoscopic capacitor with one plate a quantum conductor in the ballistic scattering regime. By determining the scattering wavefunctions in the quantum plate, we were able to obtain relevant densities of states and use them to self-consistently calculate capacitance matrix coefficients for the system. We find the capacitance to be highly dependent on the external magnetic field and the number of probes attached to the quantum conductor.
To study molecular scale systems, our approach was based on Density Functional Theory within Local Density Approximation and non-equilibrium Green's functions, implemented in the simulation package McDcal. For the work in this thesis, we modified McDcal to run on parallel computer architectures. We studied the current-voltage characteristics of silicon cage nanowires sandwiched between aluminum electrodes. We successfully analyzed our results using the complex band structure of the nanowire. Finally, we studied the capacitance properties of carbon nanotube junctions. In junctions with tubes so far apart that their wavefunctions do not overlap, we studied the variation in capacitance for different relative tube positions and radii. We also studied junctions where the nanotubes are in contact but in which there is no current due to a conductance gap. In this system we find an enhancement in the value of capacitance.
Dikeakos, Maria. "Electronic properties of amorphous and crystalline FexCo1-x-Zr2 alloys." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20141.
Full textCai, Aiguo. "Study of surface flattening kinetics by low energy electron diffraction on rutile(110)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ57094.pdf.
Full textMativetsky, Jeffrey M. "Understanding and controlling the growth of metals and molecules on an insulating surface." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102682.
Full textGoudreault, Roger D. "Some properties of the semimagnetic semiconductor alloy system Cd2x(CuGa)yMn2zTe2." Thesis, University of Ottawa (Canada), 1988. http://hdl.handle.net/10393/5499.
Full textKadel, Rajesh. "Surface structure study of imidazolium based ionic liquid." Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/1004.
Full textMarchand, Philippe. "Modèle general de la précipitation aqueuse des solides à surface rugueuse, appliqué à la ferrihydrite." Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28100.
Full textAllard, Louis Bernard. "Optical properties of two-dimensional semiconductor heterostructures: Ion implantation and carrier diffusion." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6664.
Full textDai, Ming. "Neutron irradiation damage to avalanche photodiodes and the properties of generated defects." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23880.
Full textBruyère, Michel Jean. "An ultrahigh vacuum system for the scattering of keV ions by a clean silicon(100) surface." Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5952.
Full textRen, Hong 1962. "Effects of exchange frustration on the magnetic properties of iron-rich amorphous alloys." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41224.
Full textGodin, Michel. "Design of a differential cantilever-based sensor : surface stress of self-assembled alkanethiols on gold-coated cantilevers." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30820.
Full textChristie, Iain A. D. "The magnetic properties of annite: A SQUID magnetometry and iron-57 Moessbauer spectroscopy study." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6646.
Full textLiu, Yi 1971. "First-principles study of transport properties of molecular devices : fullerene and carbon nanotube systems." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85571.
Full textWe begin with charge transport in carbon nanotubes with oxygen, and find that the interaction between oxygen molecules and carbon nanotubes significantly modifies the electronic structure near the Fermi level for both zigzag and armchair tubes. The subtle difference of the adsorption sites of oxygen and the distance between oxygen and nanotubes can cause totally different results of their transport properties.
Then we investigate current flow from the point of view of current density distribution in molecular devices, for current density gives local information of nonequilibrium transport, thereby providing useful and vivid insight to transport properties of molecular electronics. It has been found when an intrinsic carbon nanotube is doped with either a boron or a nitrogen atoms through a replacement of a carbon atom, the local physical properties around the impurity atoms (boron or nitrogen) undergo a significant change, resulting in a dramatic change of the local current distribution. It is suggested that there appears a chiral current flow in the B- and N-doped armchair nanotubes near the impurity. As for a gated C 60 molecular device, the current distribution and the total current flow are both obviously affected by the gate voltage, which indicates the importance of the gate voltage in such a molecular device.
Finally, we discuss the contact effects on transport properties of the molecular devices. We study the effects of the contact geometry as well as the electrode material and find that different orientations of C 60 connected to Au(111) leads can cause significant changes in the current-voltage (I-V) characteristics of such C60 molecular devices. On the other hand, the electrode material is crucial to obtain low resistance ohmic contacts. Our first-principles calculations of transport suggest that Ti has higher affinity for carbide formation. So the choice of proper electrode materials will play an important role in the design of nanoscale devices.
NGUYEN, TUAN ANH. "INVESTIGATIONS OF ELECTRONIC STRUCTURE AND OPTICAL PROPERTIES OF II-VI SELF-ASSEMBLED QUANTUM DOTS." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1143155352.
Full textStojak, Kristen L. "Synthesis and Properties of Polymer Nanocomposites with Tunable Electromagnetic Response." Thesis, University of South Florida, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1535889.
Full textMultifunctional polymer nanocomposites (PNCs) are attractive for the design of tunable RF and microwave components such as flexible electronics, attenuators, and antennas due to cost-effectiveness and durability of polymeric matrices. In this work, three separate PNCs were synthesized. Magnetite (Fe 3O4) and cobalt ferrite (CFO) nanoparticles, synthesized by thermal decomposition, were used as PNC fillers. Polymers used in this work were a commercial polymer provided by the Rogers Corporation (RP) and polyvinylidene fluoride (PVDF). PNCs in this thesis consist of Fe3O 4 in RP, CFO in RP, and Fe3O4 in PVDF. Characterization techniques for determining morphology of the nanoparticles, and their resulting PNCs, include x-ray diffraction, transmission electron microscopy and magnetometry.
All magnetometry measurements were taken using a Quantum Design Physical Property Measurement System with a superconducting magnet. Temperature and external magnetic field magnetization measurements revealed that all samples exhibit superparamagnetic behavior at room temperature. Blocking temperature, coercivity and reduced remnant magnetization do not vary with concentration. Tunable saturation magnetization, based on nanoparticle loading, was observed across all PNCs, regardless of polymer or nanoparticle choice, indicating that this is an inherent property in all similar PNC materials.
Tunability studies of the magneto-dielectric PNCs were carried out by adding the PNC to cavity and microstrip linear resonator devices, and passing frequencies of 1–6 GHz through them in the presence of transverse external magnetic fields of up to 4.5 kOe, provided by an electromagnet. Microwave characteristics were extracted from scattering parameters of the PNCs. In all cases, losses were reduced, quality factor was increased, and tunability of the resonance frequency was demonstrated. Strong magnetic field dependence was observed across all samples measured in this study.
Acharya, Pramod. "Charge regulation of a surface immersed in an electrolyte solution." Thesis, Florida Atlantic University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10172666.
Full textIn this thesis, we investigate theoretically a new model of charge regulation of a single charged planar surface immersed in an aqueous electrolyte solution. Assuming that the adsorbed ions are mobile in the charged plane, we formulate a field theory of charge regulation where the numbers of adsorbed ions can be determined consistently by equating the chemical potentials of the adsorbed ions to that of the ions in the bulk. We analyze the mean-field treatment of the model for electrolyte of arbitrary valences, and then beyond, where correlation effects are systematically taken into account in a loop expansion. In particular, we compute exactly various one-loop quantities, including electrostatic potentials, ion distributions, and chemical potentials, not only for symmetric (1; 1) electrolyte but also for asymmetric (2; 1) electrolyte, and make use of these quantities to address charge regulation at the one-loop level. We find that correlation effects give rise to various phase transitions in the adsorption of ions, and present phase diagrams for (1; 1) and (2; 1) electrolytes, whose distinct behaviors suggest that charge regulation, at the one-loop level, is no longer universal but depends crucially on the valency of the ions.
Kim, Jeha. "Structural and elastic properties of silver-palladium and copper-palladium superlattices." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186275.
Full textEngland, Craig Dennis. "Properties of cobalt/copper and cobalt/palladium multilayers." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185707.
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