Conductor Insulator Quantum

Transcription

1 Conductor Insulator Quantum Phase Transitions Edited by Vladimir Dobrosavljevic, Nandini Trivedi, James M. Valles, Jr. OXPORD UNIVERSITY PRESS

2 Contents List of abbreviations List of contributors xiv xvi PART I METAL-INSULATOR TRANSITIONS 1 Introduction to Metal Insulator Transitions 3 V. DOBROSAVLJEVIC 1.1 Why study metal-insulator transitions? Basic mechanisms of metal insulator transitions Current theories of the metal-insulator transition 30 Acknowledgements 58 References 58 2 Metal Insulator Transitions in Two-dimensional Electron Systems 64 S.V. KRAVCHENKO 2.1 Introduction Transport properties Magnetic properties of the electron liquid at large 7-s Comparison with theory Summary 82 Acknowledgements 82 References 82 3 Anderson Localization 86 Keith SLEVIN and Tomi OHTSUKI 3.1 Introduction Anderson localization Numerical simulations Experimental signatures of localization 106 References Penultimate Fate of a Dirty-Fermi Liquid 111 Alexander PUNNOOSE and Alexander M. FINKEL'STEIN 4.1 Experimental systems Diffusion regime Theory: background Finite-TV: one loop 116

3 x Contents 4.5 Two loops and the metal-insulator transition in the limit N -» oo Conclusions 119 Acknowledgements 119 References Numerical Studies of Metal-Insulator Transitions in Disordered Hubbard Models 121 S. CHIESA, R.T. SCALETTAR, P. CHAKRABORTY, RJ.H. DENTENEER, T. PAIVA, and S. STORY 5.1 Introduction Repulsive Hubbard model: magnetism and transport Repulsive Hubbard model: spectral function Attractive Hubbard model with site dilution Conclusions 156 Acknowledgements 157 References Dynamical Mean-field Theories of Correlation and Disorder 161 E. MIRANDA and V. DOBROSAVLJEVIC 6.1 Mott transitions in clean and disordered systems Mott-Anderson transitions: typical medium theory Mott-Anderson transitions: statistical DMFT Glassy behavior of correlated electrons Beyond DMFT: loop expansion and diffusion modes 229 Acknowledgements 236 References Visualizing Critical Correlations Near the Metal-Insulator Transition in Gai_xMnxAs 244 Ali YAZDANI 7.1 Introduction Experimental results Analysis 7.4 Multifractal Wavefunctions Conclusion 253 Acknowledgements 253 References Glassy Dynamics of Electrons Near the Metal Insulator Transition 256 Dragana POPOVIC 8.1 Introduction Metal-insulator transitions in two dimensions Glassy freezing of electrons in two dimensions Summary

4 Contents xi 8.5 Discussion 286 Acknowledgements 290 References Phase Competition and Inhomogeneous States as a New Paradigm for Complex Materials 296 Elbio DAGOTTO, Shuai DONG, Rong YU, Cengiz EN, Gonzalo ALVAREZ, and Adriana MOREO 9.1 Introduction: general aspects of phase competition Colossal magnetoresistance trapped in a box Superconducting clustered state for underdoped cuprates Other cases of inhomogeneities in model Hamiltonians for oxides Conclusions: a new paradigm has developed 324 Acknowledgements 325 References 325 PART II SUPERCONDUCTOR-INSULATOR TRANSITIONS: PRESENT STATUS AND OPEN QUESTIONS 10 Superconductor-Insulator Transitions: Present Status and Open Questions 329 Nandini TRIVEDI 10.1 Why study superconductor-insulator transitions? Energy scales in a superconductor: the amplitude-phase dichotomy Quantum phase transitions The disorder-tuned superconductor-insulator transition Superconductor-insulator transitions in clean systems The parallel-field-tuned superconductor-insulator transition The perpendicular-field-tuned superconductor-insulator transition Conclusions and open questions 347 References Scaling Analysis of Direct Superconductor-Insulator Transitions in Disordered Ultrathin Films of Metals 352 A.M. GOLDMAN 11.1 Introduction Quantum Phase Transitions Experimental Approach Thickness- and Perpendicular Magnetic Field-Tuned SI Transitions Parallel Magnetic Field SI Transition Electrostatic Control of the SI Transition Nonlinear and Hot Electron Effects Discussion 367

5 xii Contents 11.9 Conclusions 369 References Magnetic Field-Induced Novel Insulating Phase in 2D Superconductors 373 G. SAMBANDAMURTHY and N. Peter ARMITAGE 12.1 Magnetic field as the tuning parameter Novel transport properties in the insulating phase Finite-frequency behavior: superconducting correlations on the insulating side Summary 389 Acknowledgements 389 References Evidence of Cooper Pairs on the Insulating Side of the Superconductor-Insulator Transition 393 M.D. STEWART, JR. and James M. VALLES, JR Introduction: the superconducting order parameter and possible insulating phases Evidence of fermionic insulators: thin amorphous films Evidence of bosons in insulating thin amorphous films Evidence of bosons in other homogeneous films Amorphous nano-honeycomb films: direct evidence of Cooper pairs Signatures of Cooper-pair localization and comparison to other film systems 410 References Superconductor-Insulator Transitions in Ultra-thin a-pb Films: Disorder, Magnetic-field, and Magnetic-impurity Tuning 415 Peng XIONG 14.1 Introduction Experiments Experimental approach Summary 433 Acknowledgements 433 References Spin Effects Near the Superconductor-Insulator Transition 436 P.W. ADAMS 15.1 Introduction The parallel field superconductor-insulator transition Spin effects in the insulating phase Summary and zero-temperature phase diagram 455 References 457

6 Contents xiii 16 Spectroscopic Imaging STM Studies of Electronic Structure in Both the Superconducting and Pseudogap Phases of Underdoped Cuprates 459 K. FUJITA, A.R. SCHMIDT, E.-A. KIM, M.J. LAWLER, H. EISAKI, S. UCHIDA, D.-H. LEE, and J.C. DAVIS 16.1 Introduction to electronic structure of hole-doped cuprates Spectroscopic imaging scanning tunneling microscopy Doping dependence of nanoscale electronic disorder in Bi2Sr2CaCu208+( Bogoliubov quasiparticle interference imaging Low energy excitations in the superconducting phase Low-energy excitations in the pseudogap phase Broken spatial symmetries of E~ Ai states in both the dsc and PG phases Overview, conclusions, and future 483 Acknowledgements 487 References Theoretical Studies of Superconductor-Insulator Transitions 492 Yen LEE LOH and Nandini TRIVEDI 17.1 Introduction Free fermions in a random potential Disorder-tuned superconductor-insulator transition Parallel field-tuned superconductor-insulator transition Conclusions Conventions and standard formulas for imaginary-time Green's functions Derivation of Kubo formulas for electromagnetic response Electromagnetic response of Anderson model Variational Bogoliubov-de Gennes formalism 541 References Suppression of Tunneling of Superconducting Vortices Caused by a Remote Gate: Anderson's Orthogonality Catastrophe and Localization 549 K. MICHAELI and A.M. FINKEL'STEIN 18.1 Introduction Anderson's orthogonality catastrophe Tunneling with dissipative eddy currents Comparison between the orthogonality catastrophe and tunneling with dissipation Summary 564 Acknowledgements 564 References 565