Shuvaev, A., Dziom, V., Gospodarič, J., Novik, E. G., Dobretsova, A. A., Mikhailov, N. N., Kvon, Z. D., & Pimenov, A. (2022). Band Structure Near the Dirac Point in HgTe Quantum Wells with Critical Thickness. Nanomaterials, 12(14), Article 2492. https://doi.org/10.3390/nano12142492
E138-05 - Forschungsbereich Solid State Spectroscopy
Number of Pages:
Dirac fermions; band structure; cyclotron resonance; quantum wells; topological insulators
Mercury telluride (HgTe) thin films with a critical thickness of 6.5 nm are predicted to possess a gapless Dirac-like band structure. We report a comprehensive study on gated and optically doped samples by magnetooptical spectroscopy in the THz range. The quasi-classical analysis of the cyclotron resonance allowed the mapping of the band dispersion of Dirac charge carriers in a broad range of electron and hole doping. A smooth transition through the charge neutrality point between Dirac holes and electrons was observed. An additional peak coming from a second type of holes with an almost density-independent mass of around 0.04 m_0 was detected in the hole-doping range and attributed to an asymmetric spin splitting of the Dirac cone. Spectroscopic evidence for disorder-induced band energy fluctuations could not be detected in present cyclotron resonance experiments.
Materials Characterization: 50% Surfaces and Interfaces: 50%