Charge and current orders in the spin-fermion model with overlapping hot spots

TL;DR

This paper investigates the spin-fermion model with overlapping hot spots, revealing a complex phase diagram with various charge and current orders that relate to phenomena observed in underdoped cuprates.

Contribution

It introduces a detailed analysis of particle-hole instabilities in the spin-fermion model, identifying multiple competing orders including charge density waves and current phases.

Findings

Evidence for d-wave Pomeranchuk instability

Identification of charge density waves with d-form factor

Promotion of current orders by Fermi surface curvature

Abstract

Experiments carried over the last years on the underdoped cuprates have revealed a variety of symmetry-breaking phenomena in the pseudogap state. Charge-density waves, breaking of $C_{4}$ rotational symmetry as well as time-reversal symmetry breaking have all been observed in several cuprate families. In this regard, theoretical models where multiple non-superconducting orders emerge are of particular interest. We consider the recently introduced (Phys. Rev. B 93, 085131 (2016)) spin-fermion model with overlapping 'hot spots' on the Fermi surface. Focusing on the particle-hole instabilities we obtain a rich phase diagram with the chemical potential relative to the dispersion at $(0,\pi);\;(\pi,0)$ and the Fermi surface curvature in the antinodal regions being the control parameters. We find evidence for d-wave Pomeranchuk instability, d-form factor charge density waves as well as commensurate and incommensurate staggered bond current phases similar to the d-density wave state. The current orders are found to be promoted by the curvature. Considering the appropriate parameter range for the hole-doped cuprates, we discuss the relation of our results to the pseudogap state and incommensurate magnetic phases of the cuprates.