Dn. Talwar et al., LATTICE DYNAMICAL THEORY OF THERMAL-EXPANSION AND MODE GRUNEISEN PARAMETERS IN CUBIC BP, Physical review. B, Condensed matter, 55(17), 1997, pp. 11293-11299
Lattice dynamical theory of thermal expansion and mode Gruneisen param
eters in cubic boron monophosphide is reported in the quasiharmonic ap
proximation within the framework of a second-neighbor rigid-ion model.
In this scheme, we optimized the involved force constants by using no
nlinear least-squares procedures with constrained parameters and weigh
ting of the available data on critical-point phonons and elastic and l
attice constants. Theoretical results of the phonon dispersion curves
along high-symmetry directions (both at ambient and 89 kbar pressures)
, mode Gruneisen parameters, and thermal expansion coefficient (alpha(
T)) are compared and discussed with the existing experimental and ab i
nitio calculations. Consistent with x-ray data, our calcualtion for th
e variation of alpha(T) with temperature in BP is found to be remarkab
ly similar to that of beta-SiC, and unlike most other III-V-compounds,
it does not attain negative values at lower temperatures.