Proximate Dirac spin liquid in honeycomb lattice $J_1$-$J_3$ XXZ model: Numerical study and application to cobaltates
| Autor: | Bose, Anjishnu, Routh, Manodip, Voleti, Sreekar, Saha, Sudeep Kumar, Kumar, Manoranjan, Saha-Dasgupta, Tanusri, Paramekanti, Arun |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 108, 174422 (2023) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.108.174422 |
| Popis: | Recent theoretical and experimental work suggest that the honeycomb cobaltates, initially proposed as candidate Kitaev quantum magnets, are in fact described by a pseudospin-$1/2$ easy-plane spin Hamiltonian with nearest neighbor ferromagnetic (FM) exchange $J_1$ being frustrated by antiferromagnetic third-neighbor exchange $J_3$ and weaker compass anisotropies. Using exact diagonalization and density-matrix renormalization group (DMRG) calculations, we show that this model exhibits FM order at small $J_3/J_1$ and zig-zag (ZZ) order at large $J_3/J_1$, separated by an intermediate phase, which we label as $\widetilde{\mathrm{SL}}$. This $\widetilde{\mathrm{SL}}$ phase is shown to exhibit spin-liquid-like correlations in DMRG, although we cannot preclude weak broken symmetries, e.g. weak Ising type N\'eel order, given the limits on our explored system sizes. Using a modified parton mean field theory and variational Monte Carlo on Gutzwiller projected wavefunctions, we show that the optimal FM and ZZ orders as well as the intermediate $\widetilde{\mathrm{SL}}$ state are proximate to a `parent' Dirac spin liquid (SL). This Dirac SL is shown to capture the broad continuum in the temperature and magnetic field dependent terahertz spectroscopy of BaCo$_2$(AsO$_4$)$_2$, and the reported low temperature metallic thermal conductivity in Na$_2$Co$_2$TeO$_6$ and BaCo$_2$(AsO$_4$)$_2$ upon incorporating disorder induced broadening. Comment: Final PRB version - 13 pages, 11 figures. Special thanks to Federico Becca, Sasha Chernyshev, Martin Klanjsek |
| Databáze: | arXiv |
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