Specific heat and thermal expansion coefficient of AlP, AlAs and AlSb

Abstract

The temperature dependence of specific heat C V and thermal expansion coefficient α for AlP, AlAs and AlSb are studied theoretically from first principle by using the lattice dynamical method. No such experimental data are available for AlP and AlAs. The compression effect on phonon frequencies v i ( q), i.e. the mode Grüneisen parameters γ i ( q) are also computed. The theoretical values of α for AlP and AlAs become slightly negative at low temperatures (below 30 K), a fact which differs other tetrahedral crystals. Our data of γ i ( q), C v and α for AlP, AlAs and AlSb should be useful for discussing experimental information and for studying the anharmonic properties of these compounds.