Interacting Dirac fermions under spatially alternating pseudo-magnetic field: Realization of spontaneous quantum Hall effect

TL;DR

This paper investigates how strain-induced pseudo-magnetic fields in Dirac materials like graphene can lead to spontaneous quantum Hall states, revealing new topological phases driven by strain superlattices.

Contribution

It demonstrates that strain superlattices induce valley-ordered quantum Hall phases through self-consistent Hartree-Fock calculations, a novel mechanism for topological state realization.

Findings

Strain superlattices create pseudo-Landau levels in Dirac materials.

Valley-ordered states spontaneously break time-reversal symmetry.

Quantum Hall phase emerges due to strain-induced electronic structure.

Abstract

Both topological crystalline insulators surfaces and graphene host multi-valley massless Dirac fermions which are not pinned to a high-symmetry point of the Brillouin zone. Strain couples to the low-energy electrons as a time-reversal invariant gauge field, leading to the formation of pseudo-Landau levels (PLL). Here we study periodic pseudo-magnetic fields originating from strain superlattices. We study the low-energy Dirac PLL spectrum induced by the strain superlattice and analyze the effect of various polarized states. Through self-consistent Hartree-Fock calculations we establish that, due to the strain superlattice and PLL electronic structure, a valley-ordered state spontaneously breaking time-reversal and realizing a quantum Hall phase is favored, while others are suppressed.