论文标题

蜂窝状晶格中的近端狄拉克旋转液体

Proximate Dirac spin liquid in honeycomb lattice $J_1$-$J_3$ XXZ model: Numerical study and application to cobaltates

论文作者

Bose, Anjishnu, Routh, Manodip, Voleti, Sreekar, Saha, Sudeep Kumar, Kumar, Manoranjan, Saha-Dasgupta, Tanusri, Paramekanti, Arun

论文摘要

最近的理论和实验工作表明,最初提出的蜂窝堆积物实际上是由伪装 - $ 1/2 $ $ 1/2 $ easy-plane spin hamiltonian与最近的邻居铁磁性(FM)交换$ 1/2 $ j_1 $ suffifermagnetic coundmies deffifermagnetic counsey nefterneighbor $ j__3 $ j_3 $ $ j_3 $ $ j_3 $ 3 $ 3 $ 3 $ 3 $ 3 $ 33 $ 33 $ 33 $ 33 $ 3 $ 33.3 $ j 33使用精确的对角度化和密度 - 矩阵肾统计组(DMRG)计算,我们表明该模型以小$ j_3/j_1 $和Zig-Zag(ZZ)订单以大$ J_3/j_1 $的订单显示FM订单,并以中间阶段为单位,我们将其标记为$ \ didetildedeldededededededededededededededede can $} $ {这个$ \ widetilde {\ mathrm {sl}} $相位显示出在DMRG中显示旋转 - 液体样相关性,尽管我们不能排除弱弱的损坏的对称性,例如鉴于我们探索的系统尺寸的限制,弱的Ising类型Néel订单。使用修改后的Parton平均场理论和在Gutzwiller投影的波形上使用变异的蒙特卡洛,我们表明最佳FM和ZZ订单以及中间$ \ wideTilde {\ Mathrm {sl}} $状态与“父母” Dirac Spin Liquid(SL)紧密相关。该Dirac SL被证明可在温度和磁场中捕获宽阔的连续体,依赖于Terahertz baco $ _2 $(ASO $ _4 $)$ _ 2 $的Terahertz光谱,以及报告的低温金属导热率Na $ _2 $ _2 $ _2 $ _2 $ $ _2 $ _2 $ _2 $ _6 $ _6 $ _6 $ _6 $ _2 $ _2 $ _2 $ _2 $ _2 $ _222222222222222222222222222222222222岁制度。

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 Néel 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.

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