Ab initio pseudopotential calculations of InAs/AlSb heterostructures

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Abstract
The InAs/AlSb heterojunction system is a lattice matched semiconductor heterostructure with type-II band alignment at the interfaces. This system is attractive to ultrafast electronic device applications because of its high mobility and large conduction-band offset. There are two different interfaces, i.e., AlAs-like or InSb-like, for InAs/AlSb heterostructure systems, with which very different properties, such as interface roughness, mobility, and carrier concentrations, were found to be associated. There are experimental facts indicating preferential local arrangements of the interfacial atoms. In this research, first principle pseudopotential calculations are performed on InAs/AlSb superlattices associated with different interface arrangements, and their total energy is compared with that of superlattices with ideal sharp strained interfaces. The results show that superlattices with switched layers at the interfaces are more energetically favorable than superlattices with ideal sharp strained interfaces, the switching of the Al layer with the In layer at the AlAs-like interface is the most energetically favorable, with about 0.08 eV lower energy for each switch. These calculations provide more understanding about the roughness at AlAs-like interfaces in InAs/AlSb superlattices.