Physics of Novel Materials

The following sections are included:

• PREFACE

• CONTENTS

In this Chapter. I will review theoretical research on nanostructured matter performed at the University of Minnesota. My emphasis will be on pseudopotential methods which are implemented in real space. This approach allows one to examine systems which heretofore were inaccessible by ab initio methods. Illustrations of these methods will focus on clusters composed of semiconducting materials (Si, Ge and GaAs) and Si quantum dots. Comparisons will be made to recent photoemission, Raman, polarizability, and optical absorption measurements.

This article provides an introductory review, intended mainly for nonspecialists, of classical and high temperature superconductivity. After providing a historic overview, the article focuses on the macroscopic electrodynamic properties of both classical and cuprate superconductors. Next, certain aspects of the microscopic electron pairing theory of superconductivity, originally proposed by Bardeen, Cooper, and Schrieffer, are briefly summarized. followed by a discussion of josephson junctions. The structural and electronic properties unique to cuprate superconductors, as well as their superconducting pairing state symmetry and proposed pairing mechanisms, are then described. Recent progress in the development of applications is then briefly covered. Finally, the article concludes with a discussion of possible future directions.

Zeolites are crystalline porous materials with interesting physical chemistry and numerous applications. After a very brief review of their structures and applications. we focus on one recent development: the study of electrons ‘solvated’ inside a zeolite. We start by describing the optical properties of isolated solvated electrons and develop a model that can account quantitatively for them. The theory used is new. It calculates the photon absorption line shape fully quantum mechanically by taking advantage of the fact that in complex systems the spectrum is determined by the short-time motion of the nuclei after photon absorption. We then discuss the properties of fully doped zeolites, in which the system has one solvated electron in each zeolite cage. We show that even though an independent-electron band structure calculation seems to account quantitatively for most of the observed properties, it gives an erroneous qualitative description of the ground state of the material. It predicts that the material is a metal while more elaborate calculations show that it is an antiferromagnetic Mott insulator. Spin-polarized density functional theory calculations with self-interaction and generalized-gradient corrections is the only method that provides a correct description for the electronic state of the fully doped zeolite and for an interacting pair of solvated electrons.

An introduction and overview is given of the theory of spin glasses and its application.

The following sections are included:

• INTRODUCTION

• DIAMOND
  • Properties
  • Applications
  • Synthesis
    • Natural Processes
    • High Pressure
    • Low Pressure Synthesis by Chemical Vapour Deposition (CVD)
  • Ion Implantation and processing of diamond
  • Special applications for diamond
    • Radiation Hard Particle Detectors
    • Flat panel display material
  • Summary

• DIAMOND-LIKE AMORPHOUS CARBON FILMS
  • Properties and Nomenclature
  • Applications
  • Synthesis
  • Structure of ta-C
  • Dependence of Properties on sp³ content of the films
  • Electron Emission

• SUMMARY

• REFERENCES

The following sections are included:

• INTRODUCTION

• SEMICONDUCTOR HETEROSTRUCTURES

• FABRICATION OF SEMICONDUCTOR HETEROSTRUCTURES

• PHYSICAL STRUCTURE OF HETEROSTRUCTURES
  • Lattice Mismatch
  • Critical Thickness
  • Strain Relief Mechanisms
  • The Nature of Dislocations

• ELECTRONIC PROPERTIES OF HETEROSTRUCTURES
  • Composition induced effects
  • Strain induced effects
  • Size Induced Effects: Quantum Confined Systems

• SUMMARY AND CONCLUSIONS

• REFERENCES

The following sections are included:

• Introduction

• Basic Processes
  • Ion penetration and channeling
  • Ion Damage
  • Sputtering
  • Atomic Mixing

• Selected Examples of Non-equilibrium Behaviour
  • Low Temperature Oxidation and Segregation
  • SupersaturatedSolid Solutions
  • Defects and Defect-mediated Processes in Silicon
  • Cavities and Metal Accumulation in Silicon

• Amorphous Silicon: An Ideal Metastable System
  • Some Thermodynamic Properties
  • Crystallisation Kinetics of Amorphous Silicon
  • Solubility and Diffusion ln Amorphous Silicon

• Conclusions

• References

We describe systematic patterns in the experimental data for the transport properties of several types of novel material which show at least some metallic features, and mention possible explanations for some of the unusual effects observed. The materials discussed include highly-conducting polymers, high-temperature and other superconductors, alkali-doped fullerenes, glassy metals, colossal magnetoresistance materials, and spin-fluctuation metals.

The following sections are included:

• Introduction
  • Three Phases of the Physics of Anderson Localization
  • Random Interference and Diffusion
  • Coherent Back-Scattering (CBS)
  • Conditions for Phase Coherent Transport: Mesoscopic Conductors and Conductance Fluctuations

• SCATTERING MATRIX APPROACH TO SAMPLE SPECIFIC QUANTUM RESISTANCE
  • The S-matrix: 1-Channel
  • The Transfer Matrix: l-Channel
  • Four-Probe Conductance: 1-Channel
  • Two-Probe Conductance: 1-Channel
  • Generalization to an N-Channel Conductor: Thick Wire
  • Symmetry and reciprocity Relations for Conductances
  • Reservoirs, Leads, Incoherence, Dissipation, etc.

• INVARIANT IMBEDDING APPROACH TO MESOSCOPIC FLUCTUATIONS: DISORDERED WIRES
  • Invariant Imbedding: 1-Channel Case
  • Phase distribution: 1-Channel case
  • Resistance Fluctuation: 1-Channel Case
  • Multi-Channel Generalization

• STATISTICS OF CONDUCTANCE FLUCTUATIONS: AN INFORMATION THEORETIC APPROACH
  • The Maximum Entropy Method
  • Weighing the Random Matrices: The Measure
  • Probability Measure dμ(M) for the Transfer Matrices: 1-Channel case
  • Global Statistics from Local MEM: l-Channel Case
  • Generalization of MEM to the N-Channel Case (Thick Disordered Conductor): The DMPK Equation

• LIGHT PROPAGATION THROUGH A RANDOM AMPLIFYING MEDIUM: A NOVEL OPTICAL MATTER
  • Coherent Light and Coherent Amplification
  • Feedback: Non-resonant Distributed
  • Electromagnetic Wave Propagation in a Random Amplifying Medium

• References