SKM 2023 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

HL: Fachverband Halbleiterphysik

HL 17: THz and MIR physics in semiconductors

HL 17.8: Vortrag

Dienstag, 28. März 2023, 11:45–12:00, JAN 0027

Terahertz cyclotron emission from HgTe QWs — •S. Gebert^1,2, C. Consejo¹, S. Ruffenach¹, J. Torres², B. Jouault¹, and F. Teppe¹ — ¹Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS, Université de Montpellier, F-34095 Montpellier, France — ²Institut d'Electronique et des Systèmes (IES), UMR 5214 CNRS, Université de Montpellier, F-34095 Montpellier, France

Motivated by the emergence of graphene, several concepts for Landau-level (LL) lasers, tunable by a magnetic field over the whole terahertz (THz) frequency range, have been proposed. One hoped in particular was, that the non-equidistance of the LLs from Dirac fermions could efficiently suppress the non-radiative Auger recombination, which typically prevails over the radiative recombination. However, despite this non-equidistance an unfavorable non-radiative process still persists in Landau-quantized graphene, and no cyclotron emission from Dirac fermions has yet been reported. To eliminate this last non-radiative process, it is sufficient to slightly modify the dispersion of the Landau levels, e.g. by opening a small gap in the linear band structure. A proven example of such gapped graphene-like materials are HgTe quantum wells (QWs) close to the topological phase transition. We here experimentally demonstrate spontaneous Landau emission from Dirac fermions in such HgTe QWs, where the emission is tunable between 0.5 THz and 3 THz by both the magnetic field and the carrier concentration [1].

[1] S. Gebert et al., Nat. Photon. (accepted); preprint is avaliable at doi.org/10.21203/rs.3.rs-1630601/v1