On temperature effects on the structural phase transitions of GaP

Abstract

In this presentation by employing a combination of calculations based on Density Functional Theory (DFT) and Molecular Dynamics simulations (MD), we show that temperature has an unquestionable role in the behavior of Gallium Phosphide under pressure, shedding a new light in the controversial interpretation of experimental results. For example, we justify the absence of some structures predicted by early theoretical works, which remained up to now misunderstood. Moreover, we predict transitions to new structures at high temperature that may encourage new experiments. The differences in the observed transition sequences at low and high temperatures indicate that the vibrational corrections we included in the DFT calculations are fundamental to the description of the stability of higher pressure structures, and may be employed on other materials. Additionally, the good agreement between DFT and MD shows the suitability of the classical effective many-body interaction potential used to describe the different high-pressure phases of GaP in the Molecular Dynamics simulations. Finally, we discuss the behavior of GaP under extreme conditions for temperatures up to 1400 K and pressures up to 50 GPa, predicting new phases.