High-pressure isosymmetrical phase transition in calaverite

Using density functional theory, we perform ab initio calculations of the behaviour of calaverite, AuTe2, at high pressures. Calaverite has a distorted CdI2 structure, that presents a pronounced two-dimensional character and a rather anisotropic response to pressure. Increasing the pressure, we predict an isosymmetrical phase transition between 55 and 60 GPa, that is accompanied by an important distortion of the structure, observed in all its geometrical parameters, especially the c lattice parameter. Relaxing the pressure, the reverse phase transition is observed between 30 and 25 GPa.