Quantum Transport Through Graphene and Topological Insulators PDF Download
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Author: Nuno José Guimarães Couto
Publisher:
ISBN:
Category :
Languages : en
Pages : 122
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Book Description
Author: Nuno José Guimarães Couto
Publisher:
ISBN:
Category :
Languages : en
Pages : 122
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Book Description
Author: Luis E. F. Foa Torres
Publisher: Cambridge University Press
ISBN: 1108476996
Category : Science
Languages : en
Pages : 479
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Book Description
An introduction to the electrical and transport properties of graphene and other two-dimensional nanomaterials.
Author: Gregory Tkachov
Publisher: CRC Press
ISBN: 9814613266
Category : Science
Languages : en
Pages : 180
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Book Description
This book is the result of dynamic developments that have occurred in condensed matter physics after the recent discovery of a new class of electronic materials: topological insulators. A topological insulator is a material that behaves as a band insulator in its interior, while acting as a metallic conductor at its surface. The surface current car
Author: David K. Ferry
Publisher: CRC Press
ISBN: 1351796380
Category : Science
Languages : en
Pages : 538
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Book Description
Throughout their college career, most engineering students have done problems and studies that are basically situated in the classical world. Some may have taken quantum mechanics as their chosen field of study. This book moves beyond the basics to highlight the full quantum mechanical nature of the transport of carriers through nanoelectronic structures. The book is unique in that addresses quantum transport only in the materials that are of interest to microelectronics—semiconductors, with their variable densities and effective masses. The author develops Green’s functions starting from equilibrium Green’s functions and going through modern time-dependent approaches to non-equilibrium Green’s functions, introduces relativistic bands for graphene and topological insulators and discusses the quantum transport changes that these bands induce, and discusses applications such as weak localization and phase breaking processes, resonant tunneling diodes, single-electron tunneling, and entanglement. Furthermore, he also explains modern ensemble Monte Carlo approaches to simulation of various approaches to quantum transport and the hydrodynamic approaches to quantum transport. All in all, the book describes all approaches to quantum transport in semiconductors, thus becoming an essential textbook for advanced graduate students in electrical engineering or physics.
Author: Pablo Burset Atienza
Publisher: Springer Science & Business Media
ISBN: 3319011103
Category : Science
Languages : en
Pages : 166
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Book Description
The unique electronic band structure of graphene gives rise to remarkable properties when in contact with a superconducting electrode. In this thesis two main aspects of these junctions are analyzed: the induced superconducting proximity effect and the non-local transport properties in multi-terminal devices. For this purpose specific models are developed and studied using Green function techniques, which allow us to take into account the detailed microscopic structure of the graphene-superconductor interface. It is shown that these junctions are characterized by the appearance of bound states at subgap energies which are localized at the interface region. Furthermore it is shown that graphene-supercondutor-graphene junctions can be used to favor the splitting of Cooper pairs for the generation of non-locally entangled electron pairs. Finally, using similar techniques the thesis analyzes the transport properties of carbon nanotube devices coupled with superconducting electrodes and in graphene superlattices.
Author: Servet Ozdemir
Publisher: Springer Nature
ISBN: 3030883078
Category : Science
Languages : en
Pages : 142
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Book Description
This thesis presents the first systematic electron transport investigation of rhombohedral graphite (RG) films and thus lies at the interface of graphene physics, vdW heterostructure devices and topological matter. Electron transport investigation into the rhombohedral phase of graphite was limited to a few layers of graphene due to the competing hexagonal phase being more abundant. This work reports that in exfoliated natural graphite films, rhombohedral domains of up to 50 layers can be found. In the low energy limit, these domains behave as an N-layer generalisation of graphene. Moreover, being a potential alternative to twisted bilayer graphene systems, RG films show a spontaneous metal-insulator transition, with characteristic symmetry properties that could be described by mean-field theory where superconductivity is also predicted in these low energy bands. A nodal-line semimetal in the bulk limit, RG thin films are a 3D generalisation of the simplest topological insulator model: the Su-Schrieffer-Heeger chain. Similar to the more usual topological insulators, RG films exhibit parallel conduction of bulk states, which undergo three-dimensional quantum transport that reflects bulk topology.
Author: Colin Benjamin
Publisher: CRC Press
ISBN: 9781498741132
Category :
Languages : en
Pages : 368
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Book Description
This book emphasizes how new generation materials discovered recently (like graphene and topological insulators) can be understood using simple Quantum Transport Theory. The book is aimed at the reader who is just starting research in Theoretical or Experimental Physics of Dirac Materials. It will act as a good guide laying a solid ground using examples and exercise. The book could also be used as a text in Advanced Solid State/Condensed Matter Courses in Physics or Chemistry and in branches of Engineering.
Author: David K. Ferry
Publisher: CRC Press
ISBN: 1351796372
Category : Science
Languages : en
Pages : 323
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Book Description
Throughout their college career, most engineering students have done problems and studies that are basically situated in the classical world. Some may have taken quantum mechanics as their chosen field of study. This book moves beyond the basics to highlight the full quantum mechanical nature of the transport of carriers through nanoelectronic structures. The book is unique in that addresses quantum transport only in the materials that are of interest to microelectronics—semiconductors, with their variable densities and effective masses. The author develops Green’s functions starting from equilibrium Green’s functions and going through modern time-dependent approaches to non-equilibrium Green’s functions, introduces relativistic bands for graphene and topological insulators and discusses the quantum transport changes that these bands induce, and discusses applications such as weak localization and phase breaking processes, resonant tunneling diodes, single-electron tunneling, and entanglement. Furthermore, he also explains modern ensemble Monte Carlo approaches to simulation of various approaches to quantum transport and the hydrodynamic approaches to quantum transport. All in all, the book describes all approaches to quantum transport in semiconductors, thus becoming an essential textbook for advanced graduate students in electrical engineering or physics.
Author: Marc Vila Tusell
Publisher: Springer Nature
ISBN: 3030861147
Category : Technology & Engineering
Languages : en
Pages : 169
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Book Description
This thesis focuses on the exploration of nontrivial spin dynamics in graphene-based devices and topological materials, using realistic theoretical models and state-of-the-art quantum transport methodologies. The main outcomes of this work are: (i) the analysis of the crossover from diffusive to ballistic spin transport regimes in ultraclean graphene nonlocal devices, and (ii) investigation of spin transport and spin dynamics phenomena (such as the (quantum) spin Hall effect) in novel topological materials, such as monolayer Weyl semimetals WeTe2 and MoTe2. Indeed, the ballistic spin transport results are key for further interpretation of ultraclean spintronic devices, and will enable extracting precise values of spin diffusion lengths in diffusive transport and guide experiments in the (quasi)ballistic regime. Furthermore, the thesis provides an in-depth theoretical interpretation of puzzling huge measured efficiencies of the spin Hall effect in MoTe2, as well as a prediction of a novel canted quantum spin Hall effect in WTe2 with spins pointing in the yz plane.
Author: Jianxiao Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The discovery of topological states of matters has sparked intense interests amongresearchers in the past decade. Topologically non-trivial band structure in thesequantum states can give rise to a variety of topological phenomena, the experimentaldemonstration of which can have a huge impact on our understandingof fundamental states of matter. Transport measurement is one of the majorexperimental techniques to probe these topological phenomena. This dissertationis devoted to theoretical and numerical studies of quantum transport phenomenain a variety of topological materials, including magnetic topological insulator films,the quantum anomalous Hall insulator/superconductor hetero-structures, the kinkstates in bilayer graphene and the photonic crystal of topological mirror insulatorphase in the optical regime. The numerical simulations of transport phenomenaand the analytical understanding of the underlying physical mechanism in thisdissertation will provide guidance for the future transport measurements.The numerical methods to simulate quantum transport in this dissertation arebased on Landauer-Bttiker formalism and Greens function method, which willbe introduced in Chapter 2. The transmission through certain sample regionscan be extracted from the Greens function method and serves as the input forthe Landauer-Bttiker formalism to compute conductance tensor that is directlymeasured in transport experiments. Physical understanding of the transportmechanism can be provided by analyzing different components of the transmissionmatrix, in combination with other analytical methods for transport phenomena.Defects and impurities can be incorporated in numerical simulations by includingrandom potentials into the model Hamiltonian, and thus this method can be appliedin different transport regimes, from ballistic to diffusive transport.Chapter 3 to 5 of the dissertation is to apply the above numerical methodsto three different topological mesoscopic systems: magnetic topological insulator(MTI) films, quantum anomalous Hall insulator (QAHI) - superconductor (SC)junctions, and bilayer graphene devices.Chapter 3 is dedicated to the study of quantum transport through magnetictextures in a thin film of MTI. We focus on both the longitudinal and Hall transports,which reveal complicated features due to the coexistence of strong spin-orbit couplingfrom TI materials and magnetic non-colinearity from magnetic textures in thissystem. The manifested Hall transport can be induced by different topologicalmechanisms, including the intrinsic anomalous Hall effect from strong SOC and thetopological Hall effect (or known as geometric Hall effect) from magnetic textures.Thus, this system provides a nice platform to understand the interplay betweenspin-orbit coupling and real-space magnetic texture, as well as disorder scatterings.Our numerical simulations have shown different roles of spin-orbit coupling in theclean and disordered limits for this system. In the clean limit when SOC strengthis increased, the topological Hall conductance (THC) almost remains constant butthe topological Hall resistance (THR) can increase by an order of magnitude dueto the reduction of longitudinal conductance, caused by SOC-induced spin flips.However, in the disordered limit, both the THC and THR increase with increasingSOC, while longitudinal conductance is not influenced much by SOC.In Chapter 4, we study the transport of chiral edge channels in a QAHI/superconductorjunction. This type of hetero-junction has been recently fabricated andmeasured in experiments, in pursue of topological superconductivity and Majoranafermions. We focus on the disorder effect in the weak superconductor proximitylimit. Our results show that the quantized valued of conductance remains robustfor a single chiral edge channel even in the presence of disorder in the zero-biaslimit. However, such quantization is broken down for a finite bias, or for multiplechiral edge modes, or for the coexistence of a single chiral edge mode with othertrivial metallic modes, when disorders are present. Our theory provides guidanceto understand transport phenomena in these systems for future experiments.Chapter 5 is a simulation of transport behaviors through the so-called kinkstates in a bilayer graphene device under external electric and magnetic fields. Thedevice, known as a valley valve and electron beam splitter, has been fabricatedby our experimental collaborators and its unusual transport properties have beenmeasured experimentally. Our numerical simulations provide a justification of theguiding center physical picture for topological transport through this device.Chapter 6 goes beyond electronic systems and concerns topological phase inphotonic systems. We utilize a method of dynamic evolution of states to studya topological crystalline insulator phase in a photonic system. The crystallineprotection, achieved by the fine manufacturing of emulated atoms in a photoniclattice, selectively pumps incident states with a certain parity while reflects theother.The studies in the dissertation are in close collaboration with experimentalgroups, including Prof. Moses Chans and Prof. Cui-zu Changs group for the transportmeasurements in MTI films and QAHI/SC junctions, Prof. Jun Zhus groupfor the experiments on the bilayer graphene device, and Prof. Mikael Rechtsmansgroup for the photonic topological systems.
