Density-functional Tight-binding Method for Simulation of Rare-earth Mono-pnictide (RE-V):III-V

Embedding rare-earth mono-pnictide (RE-V) nanoparticles into III-V matrices allows for semiconductor composites with a wide range of optical, electrical, and thermoelectric properties. The inclusion of nanoparticles in a III-V increases the number of interfaces leading to increased phonon scattering and decreased thermal conductivity, also providing enhanced electrical conduction through electron filtering mechanisms. The electronic structure of these hybrid quantum materials at device-relevant (nm) length scales dictates functionality, yet poses challenges for ab initio simulation which is limited to systems of few hundreds up to a thousand of atoms. A promising way to simulate the electronic structure of nanoscale materials would be to combine density functional theory with an approximate method like tight binding, such as in the DFTB method. Here we discuss our parameterization of semimetallic rare-earth pnictides, III-V semiconductors, and their realistic size composite nanostructures in DFTB, and discuss effects of quantum confinement in rare-earth films on III-V substrates and rare-earth nanoparticles embedded in III-V matrices. In particular, we discuss the effects of atomic arrangements at the interface and interface orientation of the film and nanoparticle systems.