Hole Spectral Function of a Chiral Spin Liquid in the Triangular Lattice Hubbard Model

TL;DR

This study numerically analyzes the hole spectral function in a triangular lattice Hubbard model, revealing distinct signatures of different phases, including a chiral spin liquid, which can aid experimental identification.

Contribution

The paper introduces a numerical approach to compute the spectral function in a doped Hubbard model on a triangular lattice, highlighting signatures of a chiral spin liquid phase.

Findings

Distinct spectral signatures for magnetic, chiral spin liquid, and metallic phases.

Evidence of spinon dynamics in the chiral spin liquid phase.

Spectral function as a diagnostic tool for quantum spin liquids.

Abstract

Quantum spin liquids are fascinating phases of matter, hosting fractionalized spin excitations and unconventional long-range quantum entanglement. These exotic properties, however, also render their experimental characterization challenging, and finding ways to diagnose quantum spin liquids is therefore a pertinent challenge. Here, we numerically compute the spectral function of a single hole doped into the half-filled Hubbard model on the triangular lattice using techniques based on matrix product states. At half-filling the system has been proposed to realize a chiral spin liquid at intermediate interaction strength, surrounded by a magnetically ordered phase at strong interactions and a superconducting/metallic phase at weak interactions. We find that the spectra of these phases exhibit distinct signatures. By developing appropriate parton mean-field descriptions, we gain insight into the relevant low-energy features. While the magnetic phase is characterized by a dressed hole moving through the ordered spin background, we find indications of spinon dynamics in the chiral spin liquid. Our results suggest that the hole spectral function, as measured by angle-resolved photoemission spectroscopy, provides a useful tool to characterize quantum spin liquids.