Selective enhancement of Coulomb interactions in planar Weyl fermions

TL;DR

This study investigates how Coulomb interactions are selectively enhanced in planar Weyl fermions within topological 2D materials under magnetic fields, highlighting anisotropy and substrate coupling as key tuning factors.

Contribution

It demonstrates that electron-electron interactions are significantly amplified in certain Landau levels of Weyl semimetals, revealing a signature of 2D Weyl fermions influenced by anisotropy and substrate effects.

Findings

Enhanced Coulomb interactions observed in specific Landau levels.

Anisotropy in the material amplifies electron-electron interactions.

Interaction strength can be tuned via substrate coupling.

Abstract

We report on our study of the electron interaction effects in topological two-dimensional (2D) materials placed in a quantizing magnetic field. Taking our cue from a recent experimental report, we consider a particular case of bismuthene monolayer with a strong spin-orbit interaction which can be a Weyl semimetal when placed on a specially tuned substrate. Interestingly, we observe that in some Landau levels of this material, the interaction effects are strongly enhanced compared to those for a conventional 2D system. Such an enhancement of electron-electron interactions in these materials is largely due to an anisotropy present in the materials. Additionally, the interaction effects can be tuned by changing the coupling to the substrate and the strongest inter-electron interactions are observed when the system is a Weyl semimental. The observed enhancement of the interaction effects can therefore be an important signature of the 2D Weyl fermions.