Thermoemf of Ge1-XSiX single crystals under hydrostatic pressure

Abstract

The energetic structure of the conduction band of Ge and Si are well known [1} and at the atmospheric pressure the four lowest L1 germanium conduction band valleys are occupied by electron in pure Ge. In pure Si at the same conditions are occupied 1 silicium valleys. Under strong elastic pressure the 1 valleys of Ge must be involved in consideration. For this reason energy structure of strained Ge1-xSix alloy single crystal must involve four L1 and six 1-germanium valleys and six 1- silicium valleys. Under sufficiently high pressure practically all electrons will be localized in both type of 1-valleys. Under these condition the 1-valleys becomes accessible for direct experimental measurement [2,3] e, consequently, theoretical considerations of transport phenomena is no purely artificial. In this communication we try to analyze the thermoemf under high hydrostatic pressure. The theory of anisotropic scattering has been used to calculate diffusion thermoemf. The intraband scattering of electrons by acoustic phonons and impurity ions and interband non-equivalent electron scattering between L1- and 1 – valleys as well as interband equivalent f– and g - scattering between 1- valleys have been considered [4-7]. Particular cases strainless crystals and strongly strained crystals are considered as well as the case of band crossover of L1- and 1 – valleys.