Geometric orthogonal metals: Hidden antiferromagnetism and pseudogap from fluctuating stripes

TL;DR

This paper proposes a geometric orthogonal metal model driven by fluctuating domain walls, explaining the pseudogap phase in cuprates through hidden order and a transition to a Fermi liquid at a hidden quantum critical point.

Contribution

It introduces a novel geometric orthogonal metal scenario based on hidden order and fluctuating domain walls, linking antiferromagnetism, stripes, and pseudogap phases.

Findings

Hidden order with domain walls obscures antiferromagnetic order

Existence of well-defined magnetic polarons with a small Fermi surface

Transition to a Fermi liquid at a hidden quantum critical point

Abstract

One of the key features of hole-doped cuprates is the presence of an extended pseudogap phase, whose microscopic origin has been the subject of intense investigation since its discovery and is believed to be crucial for understanding high-temperature superconductivity. Various explanations have been proposed for the pseudogap, including links to symmetry-breaking orders such as stripes or pairing, and the emergence of novel fractionalized Fermi liquid (FL*) and orthogonal metal (OM) phases. The topological nature of FL* and OM phases has been identified as scenarios compatible with a small Fermi surface without symmetry breaking, as suggested experimentally. With recent experimental and numerical studies supporting an intricate relationship between stripe order and the pseudogap phase, we here propose an alternative scenario: an orthogonal metal with a geometric origin (GOM) driven by fluctuating domain walls. The essential mechanism behind our proposal is hidden order, where the proliferation of domain walls stabilized by charge fluctuations obscures the underlying long-range antiferromagnetic order in real-space, but order is preserved in the reference frame of the background spins. As a result, well-defined fermionic quasiparticles in the form of magnetic polarons exist, which couple to $\mathbb{Z}_2$ topological excitations of the domain wall string-net condensate in the ground state and constitute a small Fermi surface. At a critical doping value, we argue that hidden order is lost, driving a transition to a regular Fermi liquid at a hidden quantum critical point (hQCP) featuring quantum critical transport properties. Our GOM framework establishes a deep connection between the antiferromagnetic, stripe, and pseudogap phases, and suggests a possible unification of superconductivity in (electron and hole) doped cuprates and heavy fermion compounds.