Poster 4

Adrian Ciucivara UT-Physics

A density functional study of the effect of pressure on ferroelectric GeTe I’ll present the comparison between local density approximation (LDA) and generalized gradient approximation (GGA) calculations of GeTe as a function of applied pressure. The LDA yields a fair result for the zero pressure trigonal angle but good to excellent results for the zero pressure lattice constant, 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. I will also show results for the zero pressure cohesive energy, electric polarization, and Born effective charge, for which there are no experimental data. Except for the energy gap which is more than a factor of two too large, the GGA results are slightly better than the LDA.