Hering, M.; Ferrari, F.; Razpopov, A.; Mazin, I.I.; Valentí, R.; Jeschke, H.O.; Reuther, J.: Phase diagram of a distorted kagome antiferromagnet and application to Y-kapellasite. npj Computational Materials 8 (2022), p. 10/1-10
10.1038/s41524-021-00689-0
Open Access Version
Abstract:
We investigate the magnetism of a previously unexplored distorted spin-1/2 kagome model consisting of three symmetry-inequivalent nearest-neighbor antiferromagnetic Heisenberg couplings J_hex, J, and J', and uncover a rich ground state phase diagram even at the classical level. Using analytical arguments and numerical techniques we identify a collinear Q=0 magnetic phase, two unusual non-collinear coplanar Q=(1/3,1/3) phases and a classical spin liquid phase with a degenerate manifold of non-coplanar ground states, resembling the jammed spin liquid phase found in the context of a bond-disordered kagome antiferromagnet. We further show with density functional theory calculations that the recently synthesized Y-kapellasite Y3Cu9(OH)19Cl8 is a realization of this model and predict its ground state to lie in the region of Q=(1/3,1/3) order, which remains stable even after the inclusion of quantum fluctuation effects within variational Monte Carlo and pseudofermion functional renormalization group. The presented model opens a new direction in the study of kagome antiferromagnets.