Landau levels in spin-orbit coupling proximitized graphene: bulk states

TL;DR

This paper analyzes how magnetic fields influence Landau levels in graphene with strong spin-orbit coupling, providing analytic models to interpret experimental spectra and identify spin-orbit interaction types.

Contribution

It introduces analytic expressions for Landau levels in proximitized graphene considering various spin-orbit interactions, aiding experimental parameter extraction.

Findings

Landau levels reveal signatures of intrinsic spin-orbit coupling types.

Crossing of Landau states indicates Rashba coupling magnitude.

Magnetic response linked to large self-rotating magnetic moments.

Abstract

We study the magnetic-field dependence of Landau levels in graphene proximitized by large spin-orbit coupling materials, such as transition-metal dichalcogenides or topological insulators. In addition to the Rashba coupling, two types of intrinsic spin-orbit interactions, uniform (Kane-Mele type) and staggered (valley Zeeman type), are included, to resolve their interplay with magnetic orbital effects. Employing a continuum model approach, we derive analytic expressions for low-energy Landau levels, which can be used to extract local orbital and spin-orbit coupling parameters from scanning probe spectroscopy experiments. We compare different parameter regimes to identify fingerprints of relative and absolute magnitudes of intrinsic spin-orbit coupling in the spectra. The inverted band structure of graphene proximitized by WSe$_2$ leads to an interesting crossing of Landau states across the bulk gap at a crossover field, providing insights into the size of Rashba spin-orbit coupling. Landau level spectroscopy can help to resolve the type and signs of the intrinsic spin-orbit coupling by analyzing the symmetry in energy and number of crossings in the Landau fan chart. Finally, our results suggest that the strong response to the magnetic field of Dirac electrons in proximitized graphene can be associated with extremely large self-rotating magnetic moments.