Exploratory research

Objective

Besides its main-stream programs, nanoMIR also carries out more fundamental studies to explore the full potential of the III-Sb technology. Some of these topics may become more important in the future, or in contrast be dropped out. We give below a few examples of recent topics.

Topological phases in InAs/GaSb quantum wells

Staff: J.B. Rodriguez, E. Tournié,
PhD: S. Belemqwanssa (2021-2024), G. SIGU (2024-2027).

Projects: HYBAT (France 2030), CANTOR (ANR)

Collaborations  B. Jouault and F. Teppe, L2C, Montpellier (France), F. Hartmann and S. Höffling, U. Würzburg (Germany)

Surface states in semiconducting and insulating materials are usually fragile with respect to disorder and perturbations such as impurity scattering and many-body interactions. However, there are systems in which surface states are robust due to the non-trivial topology of the band structure. Recently, broken gap InAs/GaSb quantum wells have shown a topological insulating phase robust even to strong magnetic fields. We collaborate with our colleagues from the Physics Department of U. Montpellier (L2C, UMR CNRS 5221) and with U. Würzburg (Germany) to investigate these phases. Recent results can be found in Avogadri et al. and Belemqwanssa et al..

Thermophotovoltaic cells

Staff: P. Christol, J.-P. Perez.
Collaborations: R. Vaillon, LAAS-CNRS ; P.O. Chapuis, CETHIL Lyon.

The narrow bandgap of III-Sbs is well suited to TPV cells which aim at harvesting waste heat. We are investigating near-field TPV, with the aim to demonstrate a several-fold efficiency enhancement under near field illumination.

Ferromagnetic GaSb-based semiconductors

Staff: L. Cerutti, J.B. Rodriguez, E. Tournié,
PhD: S. Gallo (2024-2027)

Project: HYBAT (France 2030)

Collaboration: U. Tokyo

Combining the different features and functions of semiconductors and ferromagnetic materials in the same electronic devices is a promising way to create high-speed and low-power semiconductor devices for flexible information processing. Towards these goals, “ferromagnetic semiconductors (FMSs)”, where some atoms of a non-magnetic semiconductor are replaced with magnetic atoms, are the most promising material systems. It has been shown recently that InFeAs, InFeSb and GaFeSb semiconductors exhibit ferromagnetism at temperatures higher than room temperature. This project aims at integrating together the new Fe-doped FMSs and the high-performance optoelectronic devices based on the antimonide technology.