First principles prediction of structural and electronic properties of TlxIn1−xN alloy

• First principles model of ZB TlxIn1−xN hypothetical alloy using fully relativistic pseudopotentials.
• Composition dependence of the lattice constant.
• Composition dependence of the band structure, in particular the band-gap and the splitoff energy.
• The material found as a potential candidate for infrared optoelectronic applications.
• Some features of the electronic structure found typical of topological insulator.

Structural and electronic properties of zinc blende TlxIn1−xN alloy have been evaluated from first principles. The band structures have been obtained within density functional theory (DFT) with the modified Becke–Johnson (MBJLDA) approach for the exchange–correlation potential, and atoms represented by the fully relativistic pseudopotentials. The calculated band-gap dependence on Tl content in this hypothetical alloy exhibits a linear behavior up to the 25% of thallium content where its value approaches zero. In turn, the split-off energy at the ΓΓ point of the Brillouin zone, related to the spin-orbit coupling, is predicted to be comparable in value to the band-gap for relatively low thallium content of about 5%. These findings point to TlxIn1−xN alloy as a promising material for optoelectronic applications. Furthermore, the band structure of TlN reveals some specific properties exhibited by topological insulators.