Emergent dome of nematic order around a quantum anomalous Hall critical point

Abstract

We consider a model of spinful fermions on the triangular lattice which exhibits a C=2 Chern insulator (CI) phase with a quantized anomalous Hall effect, sandwiched between two normal insulator (NI) phases. The first NI-CI quantum phase transition is driven by simultaneous mass inversion of a pair of Dirac fermions, with short range interactions being perturbatively irrelevant. The second CI-NI transition is driven by a single quadratic band touching point protected by momentum space topology and C_6 lattice symmetry. A one-loop renormalization group analysis shows that short range interactions lead to a single marginally relevant perturbation at this transition. We obtain the mean field phase diagram of this model incorporating weak repulsive Hubbard interactions, finding an emergent nematic dome around this CI-NI topological phase transition. We discuss the crossovers in the anomalous Hall conductivity at nonzero temperature, and the Landau theory of the quantum and thermal transitions out of the nematic phase. Our results may be relevant to ferromagnetic double perovskite films with spin-orbit coupling which have been proposed to host such a NI-CI transition. Our work provides perhaps the simplest example of an emergent phase near a quantum phase transition.

6 pages, 2 figures: Published version

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Cited by in corpus (9)

• Magnetic skyrmion crystal at a topological insulator surface
• Spontaneous symmetry breaking of an interacting Chern insulator on a topological square lattice
• Generating and detecting topological phases with higher Chern number
• Interaction-induced phase transitions of type-II Weyl semimetals
• Individual band with higher Chern numbers in double perovskite {001} monolayers
• Emergence of superconductivity in a doped single-valley quadratic band crossing system of spin-1/2 fermions
• Repulsive Fermi gases in a two-dimensional lattice with non-Abelian gauge fields
• Emergence of asymmetric fermionic order in interacting birefringent fermions
• Nematic order in topological SYK models