AUTHOR=Martínez D. , Ruano P. L. Alcázar , Baba Y. , Arroyo-Gascón O. , Domínguez-Adame F. 

TITLE=Coherent potential approximation for disordered narrow-gap semiconductor superlattices

JOURNAL=Frontiers in Physics

VOLUME=Volume 13 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2025.1586773

DOI=10.3389/fphy.2025.1586773

ISSN=2296-424X

ABSTRACT=We introduce a solvable two-band model to study electron energy levels in disordered narrow-gap semiconductor superlattices within the k⋅p approach. The interaction of electrons with the impurities is accounted for by a separable pseudo-potential method that allows us to obtain closed expressions for the configurationally averaged Green’s function using the coherent potential approximation. This approximation is regarded as the best single-site scattering theory to calculate the average spectral properties of disordered systems. As a working example, we focus on superlattices based on IV-VI compound semiconductors and present a thorough study of the configurationally averaged density of states. Our results are compared with the predictions of a single-band model and we conclude that the latter underestimates the density of states close to the band edge.