2023/10/16 by D. A. Kozlov, J. F. Ziegler, Kozlov, D. A. +7
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Graphene research and applications #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Quantum and electron transport phenomena #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.2310.10473
openalex publication_date 2023/10/16 · openalex created_date 2023/10/18 · openalex updated_date 2026/07/28
An experimental study of Landau levels (LLs) in a system of two-dimensional massless Dirac fermions based on a critical thickness HgTe quantum well has been carried out. The magnetotransport and the capacitive response have been investigated simultaneously. It is shown that the formation of Shubnikov-de Haas (SdH) oscillations associated with odd v filling factors occurs in a magnetic field whose strength grows monotonically with v. This behavior is consistent with calculations of the electron spectrum, which predicts a decrease in cyclotron gaps with increasing v. Oscillations with even filling factors, corresponding to spin gaps, behave less trivially. First, the SdH oscillations with filling factors of 4 and higher are resolved in a magnetic field that is 2-2.5 times smaller than the field required to resolve neighboring SdH oscillations with odd filling factors of 3 and higher. This indicates a significant increase in the size of the spin gap caused by an interface inversion asymmetry (IIA) leading to Dirac cone splitting in a zero magnetic field. Using the spin splitting value gamma as a fitting parameter, we obtained the best agreement between experimental data and calculations at gamma=1.5 meV. Next, spin splitting for the zeroth and first LLs is observed in 2-3 times stronger magnetic fields than for the other levels, indicating an increase in disorder near the Dirac point, due to the lack of screening.