纳米结构中的输运PDF电子书下载

1 Introductio 1

1.1 Nanostructures:The impact 2

1.1.1 Progressing technology 2

1.1.2 Some physical considerations 4

1.2 Mesoscopic observables in nanostructures 8

1.2.1 Ballistic transport 8

1.2.2 Phase interference 11

1.2.3 Universal conductance fluctuations 13

1.2.4 Weak localization 14

1.2.5 Carrier heating in nanostructures 16

1.3 Space and time scales 18

1.4 An introduction to the subsequent chapters 19

1.5 What is omitted 21

2 Quantum confined systems 23

2.1 Nanostructure materials 24

2.2 Quantization in heterojunction system 26

2.2.1 Quantum wells and quasi-two-dimensional systems 27

2.2.2 Coupled wells and superlattices 31

2.2.3 Doped heterojunction systems and self-consistent solutions 34

2.3 Lateral confinement:Quantum wires and quantum dots 39

2.3.1 Nanolithography 39

2.3.2 Quantum wire and quantum dot structures 41

2.4 Electronic states in quantum wires and quantum dots 44

2.5 Magnetic field effects in quantum confined systems 46

2.5.1 Magnetic field in a 2DEG 47

2.5.2 Magnetic field and 1D waveguides:Edge states 51

2.6 Screening and collective excitations in low-dimensional systems 54

2.6.1 Dielectric function in quasi-2D systems 56

2.6.2 Dielectric function in quasi-1D systems 62

2.7 Homogeneous transport in low-dimensional systems 63

2.7.1 Semiclassical transport 64

2.7.2 Relaxation time approximations 66

2.7.3 Elastic scattering mechanisms 68

2.7.4 Lattice scattering 75

2.7.5 Experimental mobility in 2DEG heterostructures 81

2.7.6 Magnetotransport in quantum confined structures 84

3 Transmission in nanostructures 91

3.1 Tunneling in planar barrier structures 92

3.2 Wavefunction treatment of tunneling 96

3.2.1 Single rectangular barrier 97

3.2.2 The double barrier case 104

3.2.3 Tunneling time 111

3.3 Current in resonant tunneling diodes 113

3.3.1 Coherent tunneling 114

3.3.2 Incoherent or sequential tunneling 118

3.3.3 Space charge effects and self-consistent solutions 121

3.4 Landauer formula 124

3.5 The multi-channel case 128

3.6 Quantized conductance in nanostructures 131

3.6.1 Experimental results in quantum point contacts 131

3.6.2 Adiabatic transport model 134

3.6.3 Temperature effects 137

3.6.4 Inhomogeneous effects 138

3.6.5 Nonlinear transport 141

3.7 Transport in quantum waveguide structures 145

3.7.1 Mode-matching analysis 146

3.7.2 Transport through bends 151

3.7.3 Lateral resonant tunneling 153

3.7.4 Coupled waveguides 155

3.8 Lattice Green's function method 156

3.8.1 Single-particle Green's functions 159

3.8.2 Tight-binding Hamiltonian 161

3.8.3 Lattice Green's functions 162

3.8.4 Analytic forms of lattice Green's functions 166

3.8.5 Relation between Green's functions and S-matrix 173

3.8.6 Recursive Green's function method 174

3.8.7 Application to specific geometries 178

3.9 Multi-probe formula 181

3.9.1 Specific examples 185

3.9.2 Experimental multi-probe measurements(B=0) 191

3.10 Magnetic fields and quantum waveguides 194

3.10.1 Quantized conductance in a perpendicular field 195

3.10.2 Edge states and the quantum Hall effect 198

3.10.3 Selective population of edge states 201

4 Quantum dots and single electron phenomena 209

4.1 Electronic states in quantum dot structures 209

4.1.1 Noninteracting electrons in a parabolic potential 209

4.1.2 Dot states in a magnetic field 213

4.1.3 Multi-electron quantum dots 215

4.1.4 Quantum dot statistics 219

4.1.5 Spectroscopy of quantum dots 220

4.2 Single electron tunneling and Coulomb blockade 226

4.2.1 Introduction to Coulomb blockade and experimental studies 226

4.2.2 Orthodox theory of single electron tunneling 249

4.2.3 Co-tunneling of electrons 262

4.2.4 Coulomb blockade in semiconductor quantum dots 264

4.3 Coupled dots and quantum molecules 264

4.4 Transport in anti-dot systems 267

4.4.1 The low-magnetic field regime 268

4.4.2 The high-magnetic field regime 272

5 Interference in diffusive transport 280

5.1 Weak localization 282

5.1.1 Semiclassical treatment of the conductance 283

5.1.2 Effect of a magnetic field 286

5.1.3 Size effects in quantum wires 291

5.1.4 The magnetic decay"time" 294

5.1.5 Extension to short wires 297

5.2 Universal conductance fluctuations 299

5.3 The Green's function in transport 305

5.3.1 Interaction and self-energies 308

5.3.2 Impurity scattering 309

5.3.3 Beyond the Drude result 314

5.4 Weak-localization correction to the conductance 317

5.4.1 The cooperon correction 319

5.4.2 Role of a magnetic field 323

5.4.3 Periodic eigenvalues for the magnetic effects 325

5.5 Quantum treatment of the fluctuations 328

5.5.1 The correlation function in energy 330

5.5.2 Correlation function in a magnetic field 334

5.6 Summary of universality 336

5.6.1 The width dependence of the fluctuations 336

5.6.2 Size variation of the correlation magnetic field 338

5.6.3 Breakdown of the universality in a magnetic field 340

5.7 Fluctuations in quantum dots 346

6 Temperature decay of fluctuations 361

6.1 Temperature decay of coherence 362

6.1.1 Decay of the coherence length 363

6.1.2 Decay of the coherence time 368

6.1.3 Summary 371

6.2 The role of temperature on the fluctuations 372

6.2.1 Fluctuation amplitudes 375

6.2.2 Dimensional crossover 376

6.2.3 Correlation ranges 377

6.3 Electron-electron interaction effects 379

6.3.1 Electron energy loss in scattering 381

6.3.2 Screening and plasmons 382

6.3.3 Temperature Green's functions 386

6.3.4 One-particle density of states 391

6.3.5 The effective interaction potential 392

6.3.6 Electron-electron interactions in disordered systems-Theself-energy 403

6.4 Conductivity 408

6.5 The phase-breaking time 414

6.5.1 Interactions coupled to background fields 415

6.5.2 Modifications of the self-energy 419

7 Nonequilibrium transport and nanodevices 423

7.1 Nonequilibrium transport in mesoscopic devices 425

7.1.1 Nonequilibrium effects in tunnel barriers 426

7.1.2 Ballistic transport in vertical and planar structures 429

7.1.3 Thermopower in nanostructures 431

7.1.4 Measuring the hot electron temperature 436

7.1.5 Hot carriers in quantum dots 437

7.1.6 Breakdown of the Landaner-Büttiker formula 442

7.2 Real-time Green's functions 445

7.2.1 Equations of motion for the Green's functions 447

7.2.2 The Langreth theorem 449

7.2.3 The Green-Kubo formula 450

7.3 Transport in an inversion layer 453

7.3.1 Coulomb scattering 454

7.3.2 Surface-roughness scattering 455

7.3.3 The retarded function 458

7.3.4 The"less-than"function 463

7.4 Considerations of mesoscopic devices 465

7.4.1 A model device 465

7.4.2 Proportional coupling in the leads 469

7.4.3 A noninteracting resonant-level model 471

7.4.4 Another approach to the phonon-assisted tunneling 473

7.5 Nonequilibrium transport in high electric fields 476

7.5.1 The retarded function 477

7.5.2 The "less-than" function 482

7.5.3 Gauge-invariant formulations 484

7.6 Screening with the Airy-transformed Green's function 487

7.7 Other approaches to quantum transport in nonequilibrium systems 490

7.7.1 The density matrix 492

7.7.2 The Wigner distribution 494

Index 507