A density functional study of the effect of pressure on GeTe

We compare local density approximation (LDA) and generalized gradient approximation (GGA) calculations of GeTe as a function of applied pressure. The LDA yields a poor result for the zero pressure trigonal angle but good to excellent results for the zero pressure lattice constants, energy gap, and relative positions of the two sublattices. More importantly, it yields results within the wide range of experimental values for the critical pressure at which the ferroelectric trigonal to rock-salt transition takes place. We also calculate the zero pressure polarization.