Noncoplanar magnetic orders and gapless chiral spin liquid on the kagome lattice with staggered scalar spin chirality

Abstract

Time-reversal-symmetry-breaking three-spin interactions can suppress long-range magnetic order and stabilize quantum spin liquid states in frustrated lattices. We combine a classical approach, parton mean-field theory and variational Monte Carlo methods to study a spin-1/2 model with staggered three-spin interaction Jχ on the kagome lattice. In addition, we consider Heisenberg exchange couplings J1 on nearest-neighbor bonds and J d across the diagonals of the hexagons. In the regime of dominant Jχ, the phase diagram exhibits a gapless chiral spin liquid with a line Fermi surface. As we increase the exchange couplings, we find a variety of noncoplanar magnetic orders, including a phase that interpolates between cuboc-1 and cuboc-2 states. Our results show that the competition between induced staggered chirality and Heisenberg exchange interactions can give rise to unusual ground states of spin systems.

Chiral Broken Symmetry Descendants of the Kagomé Lattice Chiral Spin Liquid

“…Our proposed global phase diagram, as we vary spin S, hints at the possibility of unusual QSLs in the chiral model for higher spin, including spin-1 magnets, opening up a promising research direction. Previous ED and DMRG calculations have found CSLs and tetrahedral spin crystals on triangular and honeycomb lattices [9,15,17,60], and complex non-coplanar orders in kagomé lattices with staggered chiral terms which hosts a gapless CSL [61]. Our work unveils distinct noncoplanar orders on the kagomé lattice, and points to a universal connection between many-body topological order in the gapped CSL and real-space topology encoded in Berry fluxes of the non-coplanar broken symmetries.…”