Anomalous Landau quantization in intrinsic magnetic topological insulators.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37558682.
- Also identified by DOI 10.1038/s41467-023-40383-x and PMC identifier 10412595.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The intrinsic magnetic topological insulator, Mn(Bi<sub>1-x</sub>Sb<sub>x</sub>)<sub>2</sub>Te<sub>4</sub>, has been identified as a Weyl semimetal with a single pair of Weyl nodes in its spin-aligned strong-field configuration. A direct consequence of the Weyl state is the layer dependent Chern number, [Formula: see text]. Previous reports in MnBi<sub>2</sub>Te<sub>4</sub> thin films have shown higher [Formula: see text] states either by increasing the film thickness or controlling the chemical potential. A clear picture of the higher Chern states is still lacking as data interpretation is further complicated by the emergence of surface-band Landau levels under magnetic fields. Here, we report a tunable layer-dependent [Formula: see text] = 1 state with Sb substitution by performing a detailed analysis of the quantization states in Mn(Bi<sub>1-x</sub>Sb<sub>x</sub>)<sub>2</sub>Te<sub>4</sub> dual-gated devices-consistent with calculations of the bulk Weyl point separation in the doped thin films. The observed Hall quantization plateaus for our thicker Mn(Bi<sub>1-x</sub>Sb<sub>x</sub>)<sub>2</sub>Te<sub>4</sub> films under strong magnetic fields can be interpreted by a theory of surface and bulk spin-polarised Landau level spectra in thin film magnetic topological insulators.