Superconductivity

Part 1 (In Two Parts)

R. D. Parks

• Publisher: CRC Press
• Year: 2018
• eBook ISBN: 9781351412902
• Topic: Technology & Engineering
• Subtopic: Mobile & Wireless Communications
• Index: Technology & Engineering

This volume is an integrated work with a full exposition of the Bardeen-Cooper-Schrieffer theory, the Ginzburg-Landau theory, and the Gor'kov treatment of superconductivity. It discusses the fundamental experiments on macroscopic quantum phenomena and the Josephson effect.

1

EARLY EXPERIMENTS AND PHENOMENOLOGICAL THEORIES

B. S. Chandrasekhar

DEPARTMENT OF PHYSICS AND CONDENSED STATE CENTER CASE WESTERN RESERVE UNIVERSITY CLEVELAND, OHIO

I.	Introduction
	A.	Plan of the Chapter
	B.	Discovery. and Fundamental Properties
	C.	Occurrence
II.	Experimental Properties
	A.	MechanicalProperties
	B.	Thermal Properties
	C.	Electromagnetic Properties
III.	Phenomenological Theories
	A.	Thermodynamics of the Transition
	B.	Two-Fluid and Energy Gap Models
	C.	London-London-Pippard Theory
	D.	Ginzburg-Landau Theory
	E.	Prologue to the Microscopic Theory
General References
References

I. INTRODUCTION

A. Plan of the Chapter

This chapter reviews the state of our knowledge of superconductivity, both experimental and theoretical, as it was in 1957 when the microscopic theory was formulated by Bardeen, Cooper, and Schrieffer (1), which is now known universally as the BCS theory. The treatment is not historical; rather, an attempt is made to provide the background for the many topics which the succeeding chapters will discuss in detail. In the limited space available, it will not be possible to provide exhaustive compilations of experimental results or references. Representative recent references are quoted, however, and the reader is referred to them, and to the general references at the end of the chapter, for details. The first half of the chapter concerns itself with an account of the fundamental properties which distinguish a superconductor from other solids and of its behavior in mechanical, thermal, and electromagnetic fields. The latter half of the chapter discusses the thermodynamics of superconductors and the several phenomenological theories which have been proposed to explain these properties.

B. Discovery, and Fundamental Properties

Superconductivity was first discovered and so named by Kamerlingh Onnes (2) in 1911. In the course of an investigation of the electrical resistance of various metals at liquid helium temperatures, he observed that the resistance of a sample of mercury dropped from 0.08 Ω at above 4°K to less than 3 × 10⁻⁶ Ω at about 3°K, and that this drop occurred over a temperature interval of 0.01°K. There were subsequent attempts by him as well as by others to set limits to the temperature breadth of the transition and the resistance in the superconducting state. Neighbor et al. (3) have set an upper limit of 3 × 10⁻⁴ °K for the transition width in lead based on their specific heat and magnetic susceptibility measurements. Quinn and Ittner (4) observed the magnetic moment of a thin-film loop of lead carrying a persistent current as a function of time, and concluded that the resistivity in the superconducting state was less than 3.6 × 10⁻²³ Ω–cm. This is to be compared with a (probable) resistivity of ~ 10⁻⁷ Ω-cm in the normal state. While the breadth of the transition may increase if the sample is metallurgically imperfect, the extraordinary smallness of the resistance in the superconducting state appears to hold for all superconductors. Thus we arrive at the first characteristic property of a superconductor: Its electrical resistance, for all practical purposes, is zero, below a well-defi...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Preface
• Contributors to this Treatise
• 1. Early Experiments and Phenomenological Theories
• 2. The Theory of Bardeen, Cooper, and Schrieffer
• 3. Equilibrium Properties: Comparison of Experimental Results with Predictions of the BCS Theory
• 4. Nonequilibrium Properties: Comparison of Experimental Results with Predictions of the BCS Theory
• 5. The Green’s Function Method
• 6. The Ginzburg–Landau Equations and Their Extensions
• 7. Collective Modes in Superconductors
• 8. Macroscopic Quantum Phenomena
• 9. Weakly Coupled Superconductors
• 10. The Electron–Phonon Interaction and Strong-Coupling Superconductors
• 11. Tunneling and Strong-Coupling Superconductivity
• 12. Superconductivity in Low-Carrier-Density Systems: Degenerate Semiconductors