Superconductor/Semiconductor Junctions

by Schapers, Thomas; Kuhn, J.; Muller, T.; Ruckenstein, A. E.; Steiner, F.; Trumper, J.; Wolfle, P.

• ISBN13: 9783540422204
• ISBN10: 354042220X
• Format: Hardcover
• Copyright: 2001-10-01
• Publisher: Springer Verlag

Summary

This book describes superconductor/two-dimensional-electron-gas (2DEG) structures with the aim of providing a better understanding of their transport properties. The two-dimensional electron gas used for the structures described here is buried either in a III-V semiconductor heterostructure or in an inversion layer at the surface. First, the properties of a single superconductor/2DEG structure are discussed on the basis of Andreev reflection and the proximity effect. Then, the properties of superconductor/2DEG Josephson junctions are treated. The last part of the book discusses the control of junctions using gate electrodes or injection currents, and the physical effects observed in these junctions.

Table of Contents

Introduction	1	(4)
Carrier Transport Through a Superconductor/Normal-Conductor Interface	5	(16)
The Bogoliubov Equation	5	(3)
Quasiparticle Transport Through a Superconductor/Normal-Conductor Interface	8	(13)
Andreev Reflection	8	(1)
Blonder---Tinkham---Klapwijk Model	9	(5)
Inclusion of the Proximity Effect	14	(7)
Fabrication of Superconductor/Two-Dimensional-Electron-Gas Structures	21	(10)
Two-Dimensional Electron Gases	21	(5)
Two-Dimensional Electron Gases in Inversion Layers	21	(3)
Two-Dimensional Electron Gases in Heterostructures	24	(2)
Fabrication of Superconductor/Two-Dimensional-Electron-Gas/Superconductor Junctions	26	(5)
Junctions Based on a Surface Inversion Layer	27	(1)
Junctions Based on a Buried Two-Dimensional Electron Gas	28	(3)
Transport Studies on Single Superconductor/Two-Dimensional-Electron-Gas Interfaces	31	(16)
Effect of the Surface Treatment	31	(12)
Preparation of Single S/2DEG Contacts	31	(2)
Samples Cleaned by Wet Chemical Etching	33	(3)
Ar+ Sputter Cleaning	36	(5)
Electron Cyclotron Resonance Plasma Cleaning	41	(2)
Point Contact Spectroscopy	43	(4)
Superconductor/Two-Dimensional-Electron-Gas/Superconductor Junctions: Voltage-Carrying State	47	(18)
Subharmonic Gap Structures: Theoretical Models	47	(9)
Kummel---Gunsenheimer---Nicolsky Model	47	(2)
Inclusion of Normal Reflection at the SN Interface	49	(2)
Octavio---Tinkham---Blonder---Klapwijk Model	51	(2)
Inclusion of the Proximity Effect	53	(3)
Measurement of the Voltage---Carrying State	56	(5)
Andreev Current in S/2DEG/S Structures	56	(1)
Subharmonic Gap Structures	57	(3)
Subharmonic Gap Structures and the Proximity Effect	60	(1)
Resonant Structures and Interference Effects	61	(4)
Josephson Current in Superconductor/Two-Dimensional-Electron-Gas Junctions	65	(30)
Theoretical Description of the Supercurrent in an S/2DEG/S Junction	65	(12)
Supercurrent in an Ideal One-Dimensional SNS Junction	66	(2)
Supercurrent in a General One-Dimensional SNS Junction	68	(7)
Supercurrent in a Junction with a Two-Dimensional Electron Gas	75	(1)
Supercurrent in a Junction with Proximity Layers	76	(1)
Measurements of the Superconductive State	77	(18)
Current---Voltage Characteristics	78	(5)
Effect of a Magnetic Field	83	(3)
Hysteresis	86	(2)
Self-Detection of Josephson Radiation	88	(1)
Light Exposure	89	(6)
Gate-Controlled Superconductor/Two-Dimensional-Electron-Gas Junctions	95	(16)
The Josephson Field Effect Transistor	95	(5)
Interference Effects	100	(5)
Critical-Current Oscillations	100	(2)
Mesoscopic Fluctuations and Localization Effects	102	(3)
Superconducting Quantum Point Contacts	105	(6)
Nonequilibrium Josephson Current	111	(22)
Supercurrent Control by Nonequilibrium Carriers: Theoretical Concepts	111	(10)
Carrier Injection in a Three-Terminal Structure	112	(5)
Carrier Injection in a Four-Terminal Junction	117	(4)
Supercurrent Control by Nonequilibrium Carriers: Experiments	121	(12)
Carrier Injection in an InAs Step Junction	121	(2)
Multiterminal Josephson Junctions	123	(7)
Local Suppression of the Josephson Current	130	(3)
Conclusion	133	(2)
References	135	(8)
Index	143