Conditions required for nonequilibrium electrons to generate elastic waves in metals with a cubic lattice

Abstract

A model dispersion law for electrons (in the tight-binding approximation with allowance for the first and second nearest neighbors) is used for bcc crystals to analyze the shapes of the s surfaces that separate the pairs of electronic states (in the quasi-momentum space) that are potentially active for the generation (amplification) of atomic-displacement waves that control the growth of a martensite crystal under conditions of high chemical-potential gradients. For bcc and fee crystals, the following parameters are calculated: the densities of states and the fractions of the pairs of electronic states (which are potentially active for phonon generation) depending on the Fermi level μ with respect to the energy εp of a peak in the density of states at a fixed energy range |μ - ε| ≤ △ for △ = 0.2 eV. The results obtained are discussed, and it is shown that the effect of lattice distortions in the interphase region on the threshold conditions of phonon generation must be taken into account. Copyright © 2005 by Pleiades Publishing, Inc.