Enhanced nematicity emerging from higher-order van Hove singularities

Abstract

Motivated by the experimental identification of a higher-order van Hove singularity (VHS) in AV${}_3$Sb${}_5$ kagome metals, we study electronic instabilities of 2D lattice models with higher-order VHS and flavor degeneracy. In contrast to conventional VHSs, the larger power-law density of states and the weaker nesting propensity of higher-order VHSs conspire together to generate distinct competing instabilities. After discussing the occurrence of higher-order VHSs on square and kagome lattice models, we perform unbiased renormalization group calculations to study competing instabilities and find a rich phase diagram containing ferromagnetism, anti-ferromagnetism, superconductivity and Pomeranchuk orders. Remarkably, there is a generic transition from superconductivity to a $d$-wave Pomeranchuk order with increasing flavor number. Implications for the intriguing quantum states of AV${}_3$Sb${}_5$ kagome metals are also discussed.

14 pages, 10 figures

References in corpus (5)

• CsV${}_3$Sb${}_5$: a ${\mathbb{Z}}_2$ topological kagome metal with a superconducting ground state
• Unconventional Fermi surface instabilities in the Kagome Hubbard Model
• Highly-robust reentrant superconductivity in CsV3Sb5 under pressure
• Competing orders at higher-order Van Hove points
• β-YbAlB4: a critical nodal metal

Cited by in corpus (1)

• Inversion and Tunability of Van Hove Singularities in $A$V${}_3$Sb${}_5$ ($A$ = K, Rb, and Cs) kagome metals