Chiral spin liquids in triangular lattice SU(N) fermionic Mott insulators with artificial gauge fields

TL;DR

This paper demonstrates that ultra-cold fermionic Mott insulators with SU(N) symmetry on a triangular lattice, under a $rac{ ext{pi}}{2}$ artificial gauge field, can host chiral spin liquids with topological order and edge states, supported by exact diagonalizations and wave-function constructions.

Contribution

It introduces a novel chiral spin liquid phase in SU(N) fermionic Mott insulators with artificial gauge fields, supported by numerical and analytical methods.

Findings

Presence of topological order with $N$ low-lying singlet states

Chiral edge states described by $SU(N)_1$ WZNW conformal field theory

Extended chiral phase observed for $N$ between 3 and 9

Abstract

We show that, in the presence of a $\pi/2$ artificial gauge field per plaquette, Mott insulating phases of ultra-cold fermions with $SU(N)$ symmetry and one particle per site generically possess an extended chiral phase with intrinsic topological order characterized by a multiplet of $N$ low-lying singlet excitations for periodic boundary conditions, and by chiral edge states described by the $SU(N)_1$ Wess-Zumino-Novikov-Witten conformal field theory for open boundary conditions. This has been achieved by extensive exact diagonalizations for $N$ between $3$ and $9$, and by a parton construction based on a set of $N$ Gutzwiller projected fermionic wave-functions with flux $\pi/N$ per triangular plaquette. Experimental implications are briefly discussed.