Topological chiral spin liquids and competing states in triangular lattice SU($N$) Mott insulators

Abstract

SU($N$) Mott insulators have been proposed and/or realized in solid-state materials and with ultracold atoms on optical lattices. We study the two-dimensional SU($N$) antiferromagnets on the triangular lattice. Starting from an SU($N$) Heisenberg model with the fundamental representation on each site in the large-$N$ limit, we perform a self-consistent calculation and find a variety of ground states including the valence cluster states, stripe ordered states with a doubled unit-cell and topological chiral spin liquids. The system favors a cluster or ordered ground state when the number of flavors $N$ is less than 6. It is shown that, increasing the number of flavors enhances quantum fluctuations and eventually transfer the clusterized ground states into a topological chiral spin liquids. This chiral spin liquid ground state has an equivalent for the square lattice SU($N$) magnets. We further identify the corresponding lowest competing states that represent another distinct type of chiral spin liquid states. We conclude with a discussion about the relevant systems and the experimental probes.