Quantum Monte Carlo at the graphene quantum Hall edge

We study a continuum model of the interface of charge neutral graphene and vacuum in the quantum Hall regime via a sign-problem-free quantum Monte Carlo, allowing us to investigate the interplay of topology and strong interactions in a graphene quantum Hall edge for large system sizes. We focus on the topological phase transition from the spin-polarized state with symmetry-protected gapless helical edges to the fully charge gapped canted-antiferromagnet state with spontaneous symmetry breaking, driven by the Zeeman energy. Our large system size simulations allow us to detail the behavior of various quantities across this transition that are amenable to being probed experimentally, such as the spatially and energy-resolved local density of states and the local compressibility. We find peculiar kinks in the branches of the edge dispersion, and also an unexpectedly large charge susceptibility in the bulk of the canted antiferromagnet associated with its Goldstone mode.

Automated summary

This study investigates the continuum model of the interface between charge neutral graphene and vacuum in the quantum Hall regime. A quantum Monte Carlo method is used to explore the interplay of topology and strong interactions in graphene quantum Hall edges. The researchers focus on the topological phase transition and find peculiar behaviors in the edge dispersion and bulk charge susceptibility.