Fermi arcs and pseudogap in a lattice model of a doped orthogonal metal

TL;DR

This paper presents a lattice model of orthogonal metals that, through quantum Monte Carlo simulations, reproduces key features of pseudogap and Fermi arc phenomena observed in cuprates, beyond traditional Fermi liquid theory.

Contribution

It introduces a new lattice model with gauge fields and fermions that captures pseudogap and Fermi arc phenomena without symmetry breaking, providing a theoretical framework for these states.

Findings

Reproduces Fermi arc and pseudogap phenomena in simulations.

Shows confinement transition triggers superconductivity.

Restores large Fermi surface via gauge-neutral fermion hopping.

Abstract

Since the discovery of the pseudogap and Fermi arc states in underdoped cuprates, the understanding of such non-Fermi-liquid states and the associated violation of Luttinger's theorem have been the central theme in correlated electron systems. However, still lacking is a well-accepted theoretical framework to unambiguously explain these metallic states that are clearly beyond Landau's Fermi liquid and Luttinger's theorem of a Fermi surface and electron filling. Here, we design a lattice model of orthogonal metals with fermion and Ising matter fields coupled to topological order and, by solving the model via unbiased quantum Monte Carlo simulation at generic electron fillings, find that the system gives birth to phenomena of the Fermi arc and pseudogap in the single-particle spectrum that go beyond the Luttinger sum rule with broken Fermi surface but no symmetry breaking. The pseudogap and Fermi arcs coexist with a background of a deconfined Z2 gauge field, and we further find that the confinement transition of the gauge field triggers a superconductivity instability and that the hopping of the gauge-neutral fermions brings the "large" Fermi surface back from the Fermi arc state. Our unbiased numerical results provide a concrete model realization and theoretical framework for the coupling between gauge field and fermions and, in the process, generate the rich phenomena of the pseudogap, the Fermi arc, and superconductivity in generic correlated electron systems.