Oral: Signature of non-trivial band topology in Shubnikov–de Haas oscillations

We investigate the Shubnikov-de Haas (SdH) magneto-oscillations [1] in the resistivity of two-dimensional topological insulators (TIs)[2]. Within the Bernevig-Hughes-Zhang (BHZ) model for

TIs in the presence of a quantizing magnetic field, we obtain analytical expressions for the SdH oscillations by combining a semiclassical approach for the resistivity and a trace formula for the

density of states [2]. We show that when the non-trivial topology is produced by inverted bands with “Mexican-hat” or “Camel back” shape, SdH oscillations show an anomalous beating pattern that is solely due to the non-trivial topology of the system [2]. These beatings are robust against, and distinct from beatings originating from spin-orbit interactions. This provides a direct way to experimentally probe the non-trivial topology of 2D TIs entirely from a bulk measurement. Furthermore, the Fourier transform of the SdH oscillations as a function of the Fermi energy and quantum capacitance models allows for extracting both the topological gap and gap at zero momentum.

[1] DR Candido et al., PRR 5, 043297 (2023).

[2] DR Candido, SI Erlingsson and JC Egues arXiv: 2406.08977.