First principles study of the structural phase transformation of $HfO_2$ under pressure

Abstract

We investigate the phase transformation of $HfO_2$ under hydrostatic pressure through first-principles pseudopotentials calculations. Total energies are calculated within the local-density-functional approxination (LDA) and the generalized gradient approximation(GGA). We find that with increasing pressure, $HfO_2$ undergoes a series of structural transformation from monoclinic to orthorhombic-I and then to orthorhombic-II consistent with experiments. The calculated transition pressures within GGA are in good agreement with the measured values. We study the spatial charge distributions to figure out what makes transition pressures increase within GGA. We also investigate the electronic structure of $HfO_2$, a wide bandgap ionic insulator.