Theory of phase transitions under pressure in Si, Ge semiconductors

A reversible high-pressure second-order phase transition in silicon carbide ceramics SiC–BeO

“…The nonlinear increase in the thermal conductivity of test samples at rather low hydrostatic pressures of up to 100-150 MPa, where the samples experience elas tic deformation, could be indicative of a phase transi tion of the second kind [1]. A phenomenological the ory describing the changes in the properties of crystals during a phase transition of the second kind was first proposed by Landau [2] and then developed further in [1,3].…”

“…A phenomenological the ory describing the changes in the properties of crystals during a phase transition of the second kind was first proposed by Landau [2] and then developed further in [1,3].…”

“…Under the action of hydrostatic pressure, solid bodies primarily experience elastic deformation which can apparently initiate a phase transition [1]. A phenomenological theory to describe the changes in the properties of crystals in second order phase transi tions was first developed by Landau [2,3].…”

Studying equilibrium values of moduli of elasticity, using models of the mechanics of finite deformations of a continuous medium

“…The problem then arises of growing uncertainty of the analytical description, due to reducing the number of experimentally determined values of υ(σ) relating to the same phase. The particu larly acute question of the accuracy of interpolating a low number of υ(σ) values in a complex analytic dependence arises in studies in which the existence of the PT itself is established on the basis of interpolation results and the physical characteristics of the phases after the transition, as it was done in [3,4]. Below, we answer the following questions: Why do ESes of such a distinctive type produce very close results in determin ing a bulk elasticity modulus while the elasticity mod uli of the third order predicted in different models of ESMFDCM differ greatly?…”