No Band Gap, No Problem: Atomic defects in narrow bandgap materials via a band-avoiding occupation-constrained density functional theory

Le résumé fourni par la source

This final report summarized the results of the Laboratory Directed Research and Development Project No. 242427 (Exploratory Express).Development of new radiation-hard space-based infrared imaging devices, and low power high-speed electronics based upon III-V semiconductor materials is hampered by difficulties in identifying and mitigating the atomic defects responsible for debilitating radiation sensitivities.Defect-discriminating experiments are exceedingly challenging and, conversely, modeling that might provide usable insight for experimental studies is also impaired.State-of-the-art density functional theory (DFT) to characterize radiation defects is hampered by prohibitive computational cost and limited accuracy due to the DFT "band gap problem".This project developed a new method for defect calculations, a bandavoiding occupation-constrained DFT -ba-occ-DFT -that prevents the spurious occupation of band-edge states and enables total energy calculations of atomic defects uncontaminated by band edges.Application of ba-occ-DFT to indium arsenide (InAs), a simple exemplar of a family of narrow gap materials with a zero DFT gap, shows that a simple ba-occ-DFT is feasible, separates the band gap problem from the calculations of defect electronic properties, enabling rigorous calculations of defect levels (charge transition energies) in narrow-gap semiconductors despite a DFT band gap that collapses to zero.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.