Electron Spectrum of Gapless Semiconductors [Paperback]

A presentation of the peculiarities of the physical properties of a comparatively new class of solids. GSs are of practical interest since they are very sensitive to impurities, and to the influence of light, magnetic and electric fields, and to pressure.Electron Spectrum of Gapless Semiconductors presents the peculiarities of physical properties of a comparatively new class of solids - gapless semiconductors (GS). These peculiarities are determined by the main feature of the elctron spectrum, namely the absence of a gap between the conduction and valence bands. GSs form a boundary between metals and semiconductors. On the other hand GSs are of practical interest since they are very sensitive to impurities, and to the influence of light, magnetic and electric fields, and pressure.1. Introduction.- 2. Band-Structure Calculation Methods.- 2.1 Adiabatic Approximation.- 2.2 The One-Electron Hartree-Fock Approximation.- 2.2.1 The Hartree Approximation.- 2.2.2 The Hartree-Fock Method.- 2.2.3 Discrete Distribution.- 2.3 Correlation Phenomena.- 2.3.1 The Drude-Sommerfeld Gas of Free Electrons.- 2.3.2 Binding Energy.- 2.3.3 Correlation Energy.- 2.4 Methods Used to Solve the Schr?dinger Equation.- 2.4.1 General Concept.- 2.4.2 Cellular Method.- 2.4.3 Variational Methods.- 2.4.4 Classification of Computational Methods.- 2.4.5 Tight-Binding Method.- 2.4.6 The APW and KKR Methods.- 2.4.7 OPW and Pseudopotential Methods.- 2.4.8 Linear Methods.- 2.4.9 The k p-Method.- 3. Insulators, Semiconductors, Metals.- 3.1 The Detection of the Gapless State.- 3.1.1 The Very-Small Gap in HgTe.- 3.1.2 The Intrinsic Gapless Semiconductor.- 3.2 Gray Tin.- 3.2.1 Crystal Structure.- 3.2.2 Original Band Schemes.- 3.2.3 Inverse Band Model for ?-Sn.- 3.2.4 Experimental Confirmations of the Inverse-Band Model.- 3.3 Mercury Chalcogenides HgTe and HgSe.- 3.3.1 Crystal Structure and Herman?s Perturbation Method.- 3.3.2 Inverse-Band Model for II-VI Crystals.- 3.3.3 Experimental ConfirmatlS«