Physics of Dielectrics for the Engineer

Physics of Dielectrics for the Engineer is a systematic attempt to clarify and correlate advanced concepts underlying the physics of dielectrics. It reviews the basics of electrostatics, the different models for the polarizability of atoms and molecules, and the macroscopic permittivity. It also discusses the behavior of matter in an alternating field in relation to complex permittivity, the interactions between field and matter, dissipative effects under high electric fields, the wide-gap semiconductor model, the types of charge carriers, and the main disruptive processes. Organized into three parts encompassing 12 chapters, this volume begins with an overview of the physical concepts involved in the behavior of insulating materials subjected to high electric fields. It then explores the potential of a group of charges, and dipoles induced in an applied field. The book explains statistical theories of dipole orientation in an applied field and theories relating molecular and macroscopic quantities. The propagation of an electromagnetic wave, dipole relaxation of defects in crystal lattices, and space-charge polarization and relaxation are also discussed. The book explains the uni-dimensional polar lattice, intrinsic and impurity conduction in wide-gap semiconductors, thermal runaway, and collision breakdown. Many problems with corresponding solutions are included to assist the reader. This book will benefit electrical engineers, as well as electrical engineering students, scientists, and technicians.

Preface

List of Symbols

Part 1. Matter in a Constant Electric Field

I. Introduction - Condensed review of electrostatics

II. The potential of a group of charges

II.1. Multipolar expansions

II.2. Multipolar expansion of a single point charge

II.3. Multipolar expansion of a real dipole

III. Dipoles induced in an applied field

III.1. Quantum mechanical approach of electronic polarizability

III.2. Elementary models for spherical atoms and molecules

III.3. Elementary models for non-spherical atoms and molecules

III.4. Harmonic oscillator model for the ionic polarizability

IV. Statistical theories of dipole orientation in an applied field

IV.1. Case of free point dipoles (Langevin's theory)

IV.2. Case of point dipoles in crystal lattices

IV.3. Case of polarizable dipoles with Δα > O

V. Theories relating the molecular quantities to the macroscopic ones

V.1. Dilute phases

V.2. Condensed non-polar phases. Lorentz theory

V.3. Condensed phases. Onsager theory

V.4. The Kerr electro-optic effect

Part 2. Matter in an Alternating Field

VI. The complex permittivity

VI.1. Definition of ε and σ. Propagation of an electromagnetic wave

VI.2. The various types of charges and charge groups, and the corresponding interactions

VI.3. The response of a linear material to a variable field

VI.4. Case of an a.c. field. Kramers-Kronig relations

VII. Relaxations

VII.1. Introductory remarks

VII.2. Mechanical analogue of a relaxation

VII.3. Advanced formalism. Definitions and theorems

VII.4. Application to dipole relaxation - Debye relation

VII.5. The ε”(ε1) representation (Argand diagram)

VII.6. Corrections to the Debye theory

VII.7. Interfacial relaxation. Maxwell-Wagner effect

VII.8. Dipole relaxation of defects in crystal lattices

VII.9. Space-charge polarization and relaxation

VII.10. Recent work. Many-body interpretation

VIII. Resonances

VIII.1. The linear oscillator model

VIII.2. The unidimensional polar lattice

Part 3. Dissipative Effects under High Fields

IX. Insulators and wide-gap semiconductors

IX.1. Intrinsic conduction and impurity conduction

IX.2. Injection processes

X. Space-charge limited, injection-controlled conduction

X.1. Plane-parallel configuration

X.2. Cylindrical configuration

X.3. Spherical configuration

X.4. Point-plane configuration

XI. Field-induced intrinsic conduction

XI.1. The Poole-Frenkel effect

XI.2. Field-induced dissociation

XI.3. General formulation of conduction with generation and recombination of carriers

XII. Dielectric strength

XII.1.Thermal breakdown

XII.2.Intrinsic breakdown processes

XII.3.Effect of pulse duration

XII.4.Experimental procedures

General Bibliography

- Part 1

- Part 2

- Part 3

Index