Silicene (eBook)

Preface 6
Elemental 2D Materials Beyond Graphene 6
Contents 9
Contributors 15
1 A Vision on Organosilicon Chemistry and Silicene 18
1.1 Aromatic Molecules and Silicon Substituted Cyclic Rings 18
1.2 Chemical Bonding: Unsaturated Carbon Systems Versus Silicon Systems 22
1.3 Effect of Buckling Distortions in Si6 Rings: The Psuedo Jahn-Teller (PJT) Effect 24
1.4 Chemical Functionalization on Silicon Rings to Make Them Planar 26
1.5 Electron and Hole Transport in Silicene 28
1.6 Reactivity of Silicene Towards Hydrogen and Band Gap Tuning 30
1.7 Tip Enhanced Raman Spectroscopy (TERS) as a Probe for the Buckling Distortion in Silicene 33
References 37
2 Density-Functional and Tight-Binding Theory of Silicene and Silicane 39
2.1 Introduction 39
2.2 First-Principles Theory of Silicene and Silicane 41
2.2.1 Structure, Stability, and Electronic Band Structure of Silicene 41
2.2.2 Structure, Stability, and Electronic Band Structure of Silicane 44
2.3 Tight-Binding Description of Silicene and Silicane 46
2.3.1 All-Valence Tight-Binding Model of Silicene 46
2.3.2 All-Valence Tight-Binding Model of Silicane 47
2.4 Silicene in a Transverse External Electric Field 50
2.5 SO Coupling and Topological Phase Transition in Silicene 53
2.5.1 SO Induced Band Gap in Silicene 53
2.5.2 Transition from Topological Insulator to Band Insulator State 54
2.6 Summary 55
References 55
3 Electronic and Topological Properties of Silicene, Germanene and Stanene 58
3.1 Introduction 58
3.2 Graphene and Silicene 59
3.2.1 Graphene 60
3.2.2 Silicene and Tunable Band Gap 61
3.2.3 Generalized Dirac Mass Terms 64
3.3 Berry Curvature and Chern Number 64
3.3.1 TKNN Formula 64
3.3.2 Berry Curvature in Centrosymmetric System 66
3.3.3 Pontryagin Number 68
3.3.4 Classification of Topological Insulators 69
3.4 Topological Edges 70
3.4.1 Bulk-Edge Correspondence 70
3.4.2 Herical Edges and Chiral Edges 71
3.4.3 Inner Edges 71
3.4.4 Topological Kirchhoff Law 73
3.5 Topological Quantum Field-Effect Transistor 74
3.6 Impurity Effects to Topological Quantum Field-Effect Transistor 77
3.6.1 QSH Phase 78
3.6.2 QVH Phase 78
3.7 Phosphorene and Anisotropic Honeycomb Lattice 80
3.7.1 Band Structure of Anisotropic Honeycomb Nanoribbons 81
3.7.2 Topological Origin of Flat Bands 83
3.7.3 Wave Function and Energy Spectrum of Edge States 85
References 85
4 Optical Properties of Silicene and Related Materials from First Principles 87
4.1 Introduction 88
4.2 Theoretical and Numerical Methods 88
4.2.1 Atomic and Electronic Structure 88
4.2.2 Frequency-Dependent Dielectric Function 90
4.2.3 Dielectric Function and Optical Conductivity of Individual Sheets 91
4.2.4 Optical Properties of Atomically Thin Films 94
4.3 Spectra of Silicene, Germanene, and Stanene 97
4.3.1 Influence of Many-Body Effects 97
4.3.2 General Frequency Dependence 99
4.3.3 Low-Frequency Absorbance 100
4.3.4 Influence of Spin-Orbit Interaction 103
4.3.5 Reflection, Transmission, and Absorption: Global Spectra 105
4.4 Influence of Multiple Layers 106
4.4.1 Graphene Bilayer 106
4.4.2 Silicene Bilayers 108
4.5 Summary and Conclusions 110
References 111
5 Synthesis of Silicene 113
5.1 Introduction 113
5.2 The Silver Track 114
5.3 Ag(111) Mimicking a Honeycomb Lattice 117
5.4 Growth Mode and Structure Formation of Si on the Ag(111) Surface 117
5.5 Multilayer Silicene 120
5.6 Silicene Segregated on ZrB2 Thin Films 123
5.7 Synthesis of Silicene on Other Metallic Substrates 124
5.8 Concluding Remarks 125
References 125
6 Si Nanoribbons: From 1D to 3D Nanostructures 128
6.1 Introduction 128
6.2 Silicene Nanoribbons: From a Theoretical Point of View 129
6.3 The Birth of SiNRs: 1D, 2D and 3D Silicene Nano-structures on Ag(110) 131
6.3.1 Isolated SiNRs and Nanodots 131
6.3.2 Two-Dimensional Array of SiNRs 132
6.4 Oxidation of Isolated SiNRs on Ag(110) 132
6.5 Electronic Properties of 1D SiNRs and 2D Arrays of SiNRs 134
6.6 Multilayer SiNRs 134
6.7 Discussion 136
6.8 Summary 139
References 139
7 Properties of Monolayer Silicene on Ag(111) 141
7.1 Introduction 141
7.2 Expected Properties of Epitaxial Silicene 143
7.3 Formation of 2D Si-Structures on Ag(111) 144
7.3.1 Temperature-Dependence of the Si Growth on Ag(111) 146
7.4 Epitaxial (3times3) Silicene 149
7.4.1 Atomic Structure 149
7.4.2 Electronic Properties 155
7.4.3 Vibrational Properties 157
7.4.4 Temperature Dependence of the Vibrational Modes 161
7.4.5 Electron-Phonon Coupling 163
7.5 Other 2D Si Phases on Ag(111) 164
7.5.1 The Si-(sqrt13timessqrt13) Phase 164
7.5.2 The Si ``(2sqrt3times2sqrt3)'' Phase on Ag(111) 165
7.6 Stability of Silicene Layers on Ag(111) 167
7.7 Summary and Outlook 168
References 169
8 Atomic and Electronic Structure of Silicene on Ag: A Theoretical Perspective 171
8.1 The 3 times3 Reconstruction 172
8.2 The Nature of the Linear Bands 174
8.3 The sqrt3timessqrt3 Reconstruction 176
8.4 Multilayer Silicene 181
References 188
9 Silicene on Ag(111) at Low Temperatures 191
9.1 Introduction 191
9.2 Electronic Structure of the 4?×?4 Phase by STS 193
9.3 The sqrt3 timessqrt3 Phase 195
9.3.1 Dirac Fermions Evidenced by Quasi-particle Interference in the  sqrt3 timessqrt3 Phase 196
9.3.2 Dynamic Phase Transition of the  sqrt3 timessqrt3 Phase 201
9.3.3 Multilayer Silicene on Ag(111) 204
9.4 Conclusions 206
References 206
10 Synthesis of Silicene on Alternative Substrates 209
10.1 Introduction 209
10.2 Silicene/Substrate Interaction: Weak van der Waals Bonding 210
10.3 Silicene/Substrate Interaction: Covalent Bonding 216
10.4 Concluding Remarks 218
References 220
11 Surface Functionalization of Silicene 222
11.1 Introduction 222
11.2 Hydrogenation 223
11.3 Halogenation 232
11.4 Oxidization 236
11.5 Conclusion and Perspective 241
References 242
12 Encapsulated Silicene Field-Effect Transistors 245
12.1 Introduction 245
12.2 Epitaxy of Silicene on Cleavable Ag (111)/Mica Substrate 247
12.3 Air-Stability of Silicene Post Synthesis and During Transfer 249
12.3.1 Al2O3 Capping of Silicene 249
12.3.2 Ag–Si Interaction 250
12.4 Silicene Devices: Fabrication, Measurement and Electronic Properties 252
12.4.1 Silicene Encapsulated Delamination and Native Ag Electrodes (SEDNE) Process 252
12.4.2 Electrical Characterization of Silicene Field-Effect Transistors 254
12.4.3 Fundamental Physics Revealed by Prelim Electrical Measurements 259
12.5 Summary and Outlook 260
References 261
13 Germanene: Silicene's Twin Sister 265
13.1 Introduction 265
13.2 Germanene 267
13.2.1 First-Principles Calculations 267
13.2.2 Synthesis 268
13.3 Future Experiments 271
13.3.1 Anomalous Quantum Hall Effect 271
13.3.2 Quantum Spin Hall Effect 273
13.3.3 Topological Phase Transitions and Band Gap Engineering 274
13.4 Conclusions and Outlook 275
References 276
Index 278