Influence of applied pressure on bond distortions and electronic band structure of GeTe: First principle calculations

The effect of spin-orbital coupling on the lattice parameters, volume and band gap of rhombohedral (R3m) GeTe has been reported using density functional theory. The effect of applied pressure on rhombohedral GeTe has been studied. This structure has two different bond lengths for Ge-Te bond i.e. 2.86 Å and 3.24 Å. As the applied pressure increases, the both bond lengths decreases and the band gap become narrow. At a pressure of 6.47 GPa, the band gap becomes equal to zero and GeTe has semimetal phase. With pressure applied under a constraint, the larger bond length starts to decrease and the smaller bond increases. As a result, GeTe shows transition to semimetal phase at a relatively lower pressure of 2.87 GPa. The effect of pressure on band structures has been discussed in terms of atomic positions and bond lengths in the real space.