Multisubband Plasmons in InAs/GaSb Broken Gap Quantum Well

TL;DR

This paper investigates multi-subband plasmon modes in heavily doped InAs/GaSb quantum wells, demonstrating the importance of multi-band models over single-band approximations for accurate spectral predictions and highlighting their potential in quantum technology applications.

Contribution

The study introduces an 8-band ot;p model to accurately predict plasmon spectra in InAs/GaSb quantum wells, emphasizing the role of interband coupling and hybridization.

Findings

8-band ot;p model matches experimental spectra

Single-band models show qualitative discrepancies

Broken-gap wells have potential for quantum technologies

Abstract

Multi-subband plasmon (MSP) modes in heavily doped InAs/GaSb broken-gap quantum wells grown via molecular beam epitaxy (MBE) are investigated. An $8$-band $\vec{k} \cdot \vec{p}$ semiclassical model accurately predicts ellipsometric spectra, reflecting strong subband hybridization and non-parabolicity. In contrast, single-band plasmon models show qualitative discrepancies with experiment, even with adjusted effective masses. These findings highlight the potential of broken-gap wells for quantum technologies leveraging interband coupling and wavefunction hybridization.