Strong coupling between a topological insulator and a III-V heterostructure at terahertz frequency

Research Focus

• Theoretical prediction of strong coupling between the THz excitations in a topological insulator (TI) and a III-V quantum well. Provides potential material platform for optoelectronic device applications in the THz frequency domain.

Key Advances

• State-of-the-art scattering matrix method combined with Drude-Lorentz model used for semi-classical descriptions of the interaction between TI and III-V through dispersion of Dirac plasmon-phonon-intersubband transition polariton (DPPIB).
• Density functional theory calculations predict a two-dimensional hole gas at the TI-III-V interface that blueshifts the dispersion of the DPPIB.
• Guides experiments by identifying parameter ranges for which strong coupling is predicted (e.g., thickness of spacer layer, doping in quantum well). Predicts that strong coupling should be achievable for experimentally-realistic material quality, which determines loss.