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arXiv · 2107.13570

Phase diagram of a distorted kagome antiferromagnet and application to Y-kapellasite

Max Hering·Francesco Ferrari·Aleksandar Razpopov·Igor I. Mazin·Roser Valenti·Harald O. Jeschke·Johannes Reuther
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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 Jhexagon, 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 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.

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Max Hering, Francesco Ferrari, Aleksandar Razpopov, Igor I. Mazin, Roser Valenti, Harald O. Jeschke, Johannes Reuther. 2021-07-28. Phase diagram of a distorted kagome antiferromagnet and application to Y-kapellasite. https://doi.org/10.1038/s41524-021-00689-0

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