Revisiting the electronic structure of ErAs/GaAs(001) interface

Rare-earth mono-pnictides, such as ErAs, have been integrated with III-V semiconductors to form heterostructures or composite materials, aiming at applications in terahertz and thermoelectric devices, both in the form of thin films or embedded nanoparticles. These pnictides are compensated semimetals, stable in the rock salt crystal structure sharing a sub-lattice with zinc blende semiconductors such as GaAs or InGaAs. Recent developments have also aimed at transforming these rare-earth pnictides from trivial to topological semimetals under hydrostatic and epitaxial strain. Integration of these pnictides with III-V semiconductors into devices will rely on a deeper understanding of interface electronic states. Taking ErAs and GaAs as examples, we carry out first principles calculations based on hybrid density functional theory of the ErAs/GaAs(001) interface, analyzing the interface states regarding their dispersion and charge distribution both across and parallel to the interfacial plane. The results are compared with previous calculations and available experimental data.