Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 14: Poster II

HL 14.27: Poster

Monday, March 18, 2024, 15:00–18:00, Poster F

A study of Magnetic Topological Insulator MnSb₂Te₄ using the GW method — •Mohammad Farhan Tanzim and Irene Aguilera Bonet — Science Park 904, 1098 XH Amsterdam

We present GW calculations of the magnetic topological insulator MnSb₂Te₄ within the all-electron full-potential linearized augmented-plane-wave formalism. Magnetic topological insulators are materials with a narrow band gap, which is often inaccurately predicted by standard Density Functional Theory (DFT) calculations and hence, the comparison with experimental band structures is often unsatisfactory. For this reason a perturbative correction to the Kohn-Sham eigenvalues and eigenstates is necessary. We do this via many-body perturbation theory in the GW approximation. Our GW calculations show that the band gap of these materials are comparable to the experimental data. However, we do not observe the topological surface states that are characteristic of magnetic topological insulators. For this reason, we are focusing our efforts on the accurate implementation of GW calculations including both spin-orbit coupling (SOC) and magnetism. Previously, the SOC was added only as an a posteriori correction. This could be one of the reasons for not obtaining the correct orbital character of the valence and the conduction bands, which might lead to the wrong topological character and thus, account for the missing surface states. We also present progress done in that front so far.

Keywords: magnetic topological insulator; quantum anomalous hall insulator; magnetism and topoloy; qah insulators; 3D topological insulators