On the valence band offset controversy in HgTe/CdTe superlattices

Abstract

Despite a number of experimental and theoretical investigations, the long standing controversy over the value of the valence band offset ( Lambda ) in HgTe/CdTe superlattices remains unresolved. The authors present a thorough theoretical study of Lambda at the (001) and (110) interfaces. The calculations were performed using a first-principles self-consistent pseudopotential technique, including non-linear core exchange-correlation corrections, and using the local-density approximation for the exchange-correlation potential. Contrary to some previous work, rapid convergence was found with respect to the number of layers of each material included in the unit cell. A value for Lambda of 0.30 eV was obtained, independent of the interface orientation, which gives strong support for the larger experimental values of 0.35 eV.