Chiral spin liquid phase of the triangular lattice Hubbard model: a density matrix renormalization group study

TL;DR

This study uses iDMRG to investigate the triangular lattice Hubbard model at half filling, revealing an intermediate chiral spin liquid phase characterized by spontaneous time-reversal symmetry breaking and fractionalized excitations.

Contribution

It provides the first strong numerical evidence for a chiral spin liquid phase in the Hubbard model on a triangular lattice, connecting theoretical predictions with experimental signatures.

Findings

Identification of an intermediate chiral spin liquid phase

Observation of spontaneous time-reversal symmetry breaking

Detection of fractionalized spin Hall response

Abstract

Motivated by experimental studies that have found signatures of a quantum spin liquid phase in organic crystals whose structure is well described by the two-dimensional triangular lattice, we study the Hubbard model on this lattice at half filling using the infinite-system density matrix renormalization group (iDMRG) method. On infinite cylinders with finite circumference, we identify an intermediate phase between observed metallic behavior at low interaction strength and Mott insulating spin-ordered behavior at strong interactions. Chiral ordering from spontaneous breaking of time-reversal symmetry, a fractionally quantized spin Hall response, and characteristic level statistics in the entanglement spectrum in the intermediate phase provide strong evidence for the existence of a chiral spin liquid in the full two-dimensional limit of the model.