Author: Tao Li
Publisher: John Wiley & Sons
ISBN: 3527332715
Category : Technology & Engineering
Languages : en
Pages : 434
Book Description
Unique in its scope, this book comprehensively combines various synthesis strategies with applications for nanogap electrodes. Clearly divided into four parts, the monograph begins with an introduction to molecular electronics and electron transport in molecular junctions, before moving on to a whole section devoted to synthesis and characterization. The third part looks at applications with single molecules or self-assembled monolayers, and the whole is rounded off with a section on interesting phenomena observed using molecular-based devices.
Electronic Correlations in Few Layer Graphene
Author: Fan Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages : 272
Book Description
In this thesis we investigate the electronic band structures and the correlations in chirally (ABC) stacked N-layer graphene with N>̲ 2. We use ab initio density-functional theory and k · p theory to fit the parameters of a p-band tightbinding model. External potential differences between top and bottom layers are strongly screened by charge transfer but still open an energy gap at overall neutrality. Perpendicular magnetic field drives the system into the quantum Hall region with 4N-fold zero energy Landau levels. We predict that Coulomb interactions spontaneously break the SU(4N) symmetry and drive quantum Hall effects at all integer fillings n from -2N to 2N with exotic spin and pseudospin polarizations. Based on mean-field theory and perturbative renormalization group analysis, we predict that the ground state of bilayer graphene spontaneously breaks inversion symmetry for arbitrarily weak electron-electron interactions and conclude that this instability is not suppressed by quantum fluctuations but that, because of trigonal warping, it may occur only in high quality suspended bilayers. Remarkably flat conduction and valence bands that touch at charge neutrality point and Bloch states with large pseudospin chirality combine to make the bilayer graphene gapless band state strongly susceptible to a family of broken symmetry states in which each spinvalley flavor spontaneously transfers charge between layers. We explain how these states are distinguished by their charge, spin, and valley Hall conductivities, by their orbital magnetizations, and by their edge state properties. We further analyze how these competing states are influenced by Zeeman fields that couple to spin and by interlayer electric fields that couple to layer pseudospin, and comment on the possibility of using response and edge state signatures to identify the character of the bilayer ground state experimentally. We demonstrate that similar insulating broken symmetry states and spontaneous topological orders also occur in bilayer's thicker cousins, chirally stacked multilayer graphene systems.
Publisher:
ISBN:
Category :
Languages : en
Pages : 272
Book Description
In this thesis we investigate the electronic band structures and the correlations in chirally (ABC) stacked N-layer graphene with N>̲ 2. We use ab initio density-functional theory and k · p theory to fit the parameters of a p-band tightbinding model. External potential differences between top and bottom layers are strongly screened by charge transfer but still open an energy gap at overall neutrality. Perpendicular magnetic field drives the system into the quantum Hall region with 4N-fold zero energy Landau levels. We predict that Coulomb interactions spontaneously break the SU(4N) symmetry and drive quantum Hall effects at all integer fillings n from -2N to 2N with exotic spin and pseudospin polarizations. Based on mean-field theory and perturbative renormalization group analysis, we predict that the ground state of bilayer graphene spontaneously breaks inversion symmetry for arbitrarily weak electron-electron interactions and conclude that this instability is not suppressed by quantum fluctuations but that, because of trigonal warping, it may occur only in high quality suspended bilayers. Remarkably flat conduction and valence bands that touch at charge neutrality point and Bloch states with large pseudospin chirality combine to make the bilayer graphene gapless band state strongly susceptible to a family of broken symmetry states in which each spinvalley flavor spontaneously transfers charge between layers. We explain how these states are distinguished by their charge, spin, and valley Hall conductivities, by their orbital magnetizations, and by their edge state properties. We further analyze how these competing states are influenced by Zeeman fields that couple to spin and by interlayer electric fields that couple to layer pseudospin, and comment on the possibility of using response and edge state signatures to identify the character of the bilayer ground state experimentally. We demonstrate that similar insulating broken symmetry states and spontaneous topological orders also occur in bilayer's thicker cousins, chirally stacked multilayer graphene systems.
Electron Correlation Effects in Strained Dual-layer Graphene Systems
Author: Peter Karl Harnish
Publisher:
ISBN:
Category :
Languages : en
Pages : 124
Book Description
In low dimensional systems, electron correlation effects can often be enhanced. This can be vital since these effects not only play an important role in the study of many-electron physics, but are also useful in designing new materials for various applications. Since its isolation from graphite in 2004, graphene, a two dimensional sheet of carbon atoms, has drawn considerable interest due to its remarkable properties. In the past few years, research has moved on from single to bi-, dual- and multi-layer graphene systems, each displaying their own multitudes of intriguing properties. In particular, multi-layer systems that are electronically decoupled, but still coupled via the long-range Coulomb interaction, are very fascinating as they provide an opportunities to study phenomena like excitonic condensates, non-zero band gaps and van der Waals (vdW) interactions. In this thesis, I shall discuss our recent work on two different physical aspects of dual- layer graphene systems under uniaxial strain. Firstly, I shall present results on the vdW correlation energy evaluated, within the Random Phase Approximation, at zero temperature between two undoped graphene layers separated by a finite distance. The correlation energy is obtained for three anisotropic models with variations in the strength of the effective coupling constant. We find that the vdW interaction energy increases with increasing anisotropy and the many-body contributions to the correlation energy are non-negligible. In the second part, I shall talk about the formation of inter-layer electron-hole (excitonic) pairings, caused by the inter-layer Coulomb interaction between two uniaxially strained graphene sheets which are appropriately doped with electrons/holes and our studies of the dependence of strain on the effective interaction. We find that strain, in combination with precise control of the initial momentum can effectively overcome the suppression due to inter-layer screening effects.
Publisher:
ISBN:
Category :
Languages : en
Pages : 124
Book Description
In low dimensional systems, electron correlation effects can often be enhanced. This can be vital since these effects not only play an important role in the study of many-electron physics, but are also useful in designing new materials for various applications. Since its isolation from graphite in 2004, graphene, a two dimensional sheet of carbon atoms, has drawn considerable interest due to its remarkable properties. In the past few years, research has moved on from single to bi-, dual- and multi-layer graphene systems, each displaying their own multitudes of intriguing properties. In particular, multi-layer systems that are electronically decoupled, but still coupled via the long-range Coulomb interaction, are very fascinating as they provide an opportunities to study phenomena like excitonic condensates, non-zero band gaps and van der Waals (vdW) interactions. In this thesis, I shall discuss our recent work on two different physical aspects of dual- layer graphene systems under uniaxial strain. Firstly, I shall present results on the vdW correlation energy evaluated, within the Random Phase Approximation, at zero temperature between two undoped graphene layers separated by a finite distance. The correlation energy is obtained for three anisotropic models with variations in the strength of the effective coupling constant. We find that the vdW interaction energy increases with increasing anisotropy and the many-body contributions to the correlation energy are non-negligible. In the second part, I shall talk about the formation of inter-layer electron-hole (excitonic) pairings, caused by the inter-layer Coulomb interaction between two uniaxially strained graphene sheets which are appropriately doped with electrons/holes and our studies of the dependence of strain on the effective interaction. We find that strain, in combination with precise control of the initial momentum can effectively overcome the suppression due to inter-layer screening effects.
Graphene And Its Fascinating Attributes
Author: Swapan K Pati
Publisher: World Scientific
ISBN: 9814462551
Category : Science
Languages : en
Pages : 287
Book Description
Graphene, a single sheet of graphite, has an unconventional electronic structure that can be described in terms of massless Dirac Fermions. This interesting electronic feature is not only an important fundamental issue in condensed matter physics but also holds future promise in post-Si electronic/spintronics device applications.Graphene is the most fundamental building block, with which a variety of carbon-based materials such as graphite, fullerene and carbon nanotubes can be created. The diverse chemical, electronic and magnetic properties of nanographene and graphene are mainly due to their geometrical electronic structure. This book presents the frontiers of graphene research ranging from important issues in condensed matter physics and chemistry to advanced device applications.
Publisher: World Scientific
ISBN: 9814462551
Category : Science
Languages : en
Pages : 287
Book Description
Graphene, a single sheet of graphite, has an unconventional electronic structure that can be described in terms of massless Dirac Fermions. This interesting electronic feature is not only an important fundamental issue in condensed matter physics but also holds future promise in post-Si electronic/spintronics device applications.Graphene is the most fundamental building block, with which a variety of carbon-based materials such as graphite, fullerene and carbon nanotubes can be created. The diverse chemical, electronic and magnetic properties of nanographene and graphene are mainly due to their geometrical electronic structure. This book presents the frontiers of graphene research ranging from important issues in condensed matter physics and chemistry to advanced device applications.
Electronic Transport in Few-layer Graphene
Author: Zeng Zhao
Publisher:
ISBN: 9781303712432
Category : Graphene
Languages : en
Pages : 149
Book Description
Future work in this area include (1) using in-plane magnetic field effect to probe few layer graphene to determine their dependence on total spin, (2) top-gated heterojunction devices to locally control the carrier density and band structure of the two regions, (3) other layered materials, such as topological insulators and transition metal dichalcogenides. These studies could contribute to both our fundamental understanding of low-dimensional physics and technology applications.
Publisher:
ISBN: 9781303712432
Category : Graphene
Languages : en
Pages : 149
Book Description
Future work in this area include (1) using in-plane magnetic field effect to probe few layer graphene to determine their dependence on total spin, (2) top-gated heterojunction devices to locally control the carrier density and band structure of the two regions, (3) other layered materials, such as topological insulators and transition metal dichalcogenides. These studies could contribute to both our fundamental understanding of low-dimensional physics and technology applications.
Electronic Transport Properties of Few-Layer Graphene Materials
Author: S. Russo
Publisher:
ISBN:
Category : Science
Languages : en
Pages :
Book Description
Electronic Transport Properties of Few-Layer Graphene Materials.
Publisher:
ISBN:
Category : Science
Languages : en
Pages :
Book Description
Electronic Transport Properties of Few-Layer Graphene Materials.
Nanogap Electrodes
Author: Tao Li
Publisher: John Wiley & Sons
ISBN: 3527332715
Category : Technology & Engineering
Languages : en
Pages : 434
Book Description
Unique in its scope, this book comprehensively combines various synthesis strategies with applications for nanogap electrodes. Clearly divided into four parts, the monograph begins with an introduction to molecular electronics and electron transport in molecular junctions, before moving on to a whole section devoted to synthesis and characterization. The third part looks at applications with single molecules or self-assembled monolayers, and the whole is rounded off with a section on interesting phenomena observed using molecular-based devices.
Publisher: John Wiley & Sons
ISBN: 3527332715
Category : Technology & Engineering
Languages : en
Pages : 434
Book Description
Unique in its scope, this book comprehensively combines various synthesis strategies with applications for nanogap electrodes. Clearly divided into four parts, the monograph begins with an introduction to molecular electronics and electron transport in molecular junctions, before moving on to a whole section devoted to synthesis and characterization. The third part looks at applications with single molecules or self-assembled monolayers, and the whole is rounded off with a section on interesting phenomena observed using molecular-based devices.
Geometric and Electronic Properties of Graphene-Related Systems
Author: Ngoc Thanh Thuy Tran
Publisher: CRC Press
ISBN: 1351368478
Category : Science
Languages : en
Pages : 316
Book Description
Due to its physical, chemical, and material properties, graphene has been widely studied both theoretically and experimentally since it was first synthesized in 2004. This book explores in detail the most up-to-date research in graphene-related systems, including few-layer graphene, sliding bilayer graphene, rippled graphene, carbon nanotubes, and adatom-doped graphene, among others. It focuses on the structure-, stacking-, layer-, orbital-, spin- and adatom-dependent essential properties, in which single- and multi-orbital chemical bondings can account for diverse phenomena. Geometric and Electronic Properties of Graphene-Related Systems: Chemical Bonding Schemes is excellent for graduate students and researchers, but understandable to undergraduates. The detailed theoretical framework developed in this book can be used in the future characterization of emergent materials.
Publisher: CRC Press
ISBN: 1351368478
Category : Science
Languages : en
Pages : 316
Book Description
Due to its physical, chemical, and material properties, graphene has been widely studied both theoretically and experimentally since it was first synthesized in 2004. This book explores in detail the most up-to-date research in graphene-related systems, including few-layer graphene, sliding bilayer graphene, rippled graphene, carbon nanotubes, and adatom-doped graphene, among others. It focuses on the structure-, stacking-, layer-, orbital-, spin- and adatom-dependent essential properties, in which single- and multi-orbital chemical bondings can account for diverse phenomena. Geometric and Electronic Properties of Graphene-Related Systems: Chemical Bonding Schemes is excellent for graduate students and researchers, but understandable to undergraduates. The detailed theoretical framework developed in this book can be used in the future characterization of emergent materials.
Electronic Properties of Few-layer Twistronic Graphene
Electronic Properties of Suspended Few-layer Graphene Membranes
Author: Kevin Scott Myhro
Publisher:
ISBN: 9780355472622
Category : Field-effect transistors
Languages : en
Pages : 131
Book Description
Graphene, the two-dimensional (2D) honeycomb lattice of sp2-hybrized carbon atoms, has emerged as a "wonder" material with unique properties, such as its linear energy dispersion with massless Dirac fermions, so-called half-integer quantum Hall (QH) effect, unparalleled tensile strength, and high optical transparency and thermal conductivity. Its few-layer counterparts have similar mechanical but remarkably different electrical properties, including layer- and stacking-dependent band structures, massive charge carriers, and energy gaps that may arise from single particle effect as well as electronic interactions.
Publisher:
ISBN: 9780355472622
Category : Field-effect transistors
Languages : en
Pages : 131
Book Description
Graphene, the two-dimensional (2D) honeycomb lattice of sp2-hybrized carbon atoms, has emerged as a "wonder" material with unique properties, such as its linear energy dispersion with massless Dirac fermions, so-called half-integer quantum Hall (QH) effect, unparalleled tensile strength, and high optical transparency and thermal conductivity. Its few-layer counterparts have similar mechanical but remarkably different electrical properties, including layer- and stacking-dependent band structures, massive charge carriers, and energy gaps that may arise from single particle effect as well as electronic interactions.
Graphene Chemistry
Author: De-en Jiang
Publisher: John Wiley & Sons
ISBN: 1119942128
Category : Technology & Engineering
Languages : en
Pages : 496
Book Description
What are the chemical aspects of graphene as a novel 2D material and how do they relate to the molecular structure? This book addresses these important questions from a theoretical and computational standpoint. Graphene Chemistry: Theoretical Perspectives presents recent exciting developments to correlate graphene’s properties and functions to its structure through state-of-the-art computational studies. This book focuses on the chemistry aspect of the structure-property relationship for many fascinating derivatives of graphene; various properties such as electronic structure, magnetism, and chemical reactivity, as well as potential applications in energy storage, catalysis, and nanoelectronics are covered. The book also includes two chapters with significant experimental portions, demonstrating how deep insights can be obtained by joint experimental and theoretical efforts. Topics covered include: Graphene ribbons: Edges, magnetism, preparation from unzipping, and electronic transport Nanographenes: Properties, reactivity, and synthesis Clar sextet rule in nanographene and graphene nanoribbons Porous graphene, nanomeshes, and graphene-based architecture and assemblies Doped graphene: Theory, synthesis, characterization and applications Mechanisms of graphene growth in chemical vapor deposition Surface adsorption and functionalization of graphene Conversion between graphene and graphene oxide Applications in gas separation, hydrogen storage, and catalysis Graphene Chemistry: Theoretical Perspectives provides a useful overview for computational and theoretical chemists who are active in this field and those who have not studied graphene before. It is also a valuable resource for experimentalist scientists working on graphene and related materials, who will benefit from many concepts and properties discussed here.
Publisher: John Wiley & Sons
ISBN: 1119942128
Category : Technology & Engineering
Languages : en
Pages : 496
Book Description
What are the chemical aspects of graphene as a novel 2D material and how do they relate to the molecular structure? This book addresses these important questions from a theoretical and computational standpoint. Graphene Chemistry: Theoretical Perspectives presents recent exciting developments to correlate graphene’s properties and functions to its structure through state-of-the-art computational studies. This book focuses on the chemistry aspect of the structure-property relationship for many fascinating derivatives of graphene; various properties such as electronic structure, magnetism, and chemical reactivity, as well as potential applications in energy storage, catalysis, and nanoelectronics are covered. The book also includes two chapters with significant experimental portions, demonstrating how deep insights can be obtained by joint experimental and theoretical efforts. Topics covered include: Graphene ribbons: Edges, magnetism, preparation from unzipping, and electronic transport Nanographenes: Properties, reactivity, and synthesis Clar sextet rule in nanographene and graphene nanoribbons Porous graphene, nanomeshes, and graphene-based architecture and assemblies Doped graphene: Theory, synthesis, characterization and applications Mechanisms of graphene growth in chemical vapor deposition Surface adsorption and functionalization of graphene Conversion between graphene and graphene oxide Applications in gas separation, hydrogen storage, and catalysis Graphene Chemistry: Theoretical Perspectives provides a useful overview for computational and theoretical chemists who are active in this field and those who have not studied graphene before. It is also a valuable resource for experimentalist scientists working on graphene and related materials, who will benefit from many concepts and properties discussed here.