Role of Hund's splitting in electronic phase competition inPb1−xSnxTe

Abstract

We study the effect of Hund's splitting of repulsive interactions on electronic phase transitions in the multiorbital topological crystalline insulator ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Sn}}_{x}\mathrm{Te}$ when the chemical potential is tuned to the vicinity of low-lying type-II Van Hove singularities. Nontrivial Berry phases associated with the Bloch states impart momentum dependence to electron interactions in the relevant band. We use a multipatch parquet renormalization-group (RG) analysis to study the competition of different electronic phases, and we find that if the dominant fixed-point interactions correspond to antiparallel spin configurations, then a chiral $p$-wave Fulde-Ferrell-Larkin-Ovchinnikov state is favored, otherwise none of the commonly encountered electronic instabilities occurs within the one-loop parquet RG approach.