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

Journal Article · 19 January 2022 · npj Computational Materials

DOI: https://doi.org/10.1038/s41524-021-00689-0 · OSTI ID:1841289

Hering, Max ; Ferrari, Francesco ; Razpopov, Aleksandar; Mazin, Igor I. ; Valentí, Roser; Jeschke, Harald O. ; Reuther, Johannes

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 _⬡ , J , and $$$$J^{\prime}$$$$ $J^{\prime }$ , and uncover a rich ground state phase diagram even at the classical level. Using analytical arguments and numerical techniques we identify a collinear $$$$\overrightarrow{Q}=0$$$$ $\overrightarrow{Q}=0$ magnetic phase, two unusual non-collinear coplanar $$$$\overrightarrow{Q}=(1/3,1/3)$$$$ $\overrightarrow{Q}=\left(1/3,1/3\right)$ phases and a classical spin liquid phase with a degenerate manifold of non-coplanar ground states, resembling the jammed spin liquid phase found in the context of a bond-disordered kagome antiferromagnet. We further show with density functional theory calculations that the recently synthesized Y-kapellasite Y ₃ Cu ₉ (OH) ₁₉ Cl ₈ is a realization of this model and predict its ground state to lie in the region of $$$$\overrightarrow{Q}=(1/3,1/3)$$$$ $\overrightarrow{Q}=\left(1/3,1/3\right)$ 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.

• Sponsoring Organization: USDOE
• Grant/Contract Number: NONE; SC0021089
• OSTI ID: 1841289
• Journal Information: npj Computational Materials, Journal Name: npj Computational Materials Journal Issue: 1 Vol. 8; ISSN 2057-3960
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: United Kingdom
• Language: English