HgTe/CdTe heterostructure under perturbations preserving time reversal symmetry: a density functional theory study

The Dirac-like spin states at the interfaces of HgTe/CdTe heterostructures are predicted to be robust against perturbations preserving time-reversal symmetry. However, these perturbations will certainly affect these interface states. In this work we use the density functional theory to study the behavior of these interface states under external pressure and electric fields. Differently from the three-dimensional topological insulators, the HgTe/CdTe interface states present fully in-plane Rashba-like spin texture. Further, biaxial external pressures and electric fields perpendicular to the interfaces are seen to change the energetics and dispersion of the protected states, modifying the energy ordering of the crossing of the polarized interface states inside the band structure, and altering their Fermi velocities while not changing the topological quantum phase.