标题： CeTa$_7$O$_{19}$的可能量子自旋液体态 显示英文标题

标题： Possible quantum spin liquid state of CeTa$_7$O$_{19}$

摘要： CeTa$_7$O$_{19}$是一种最近发现的二维三角晶格反铁磁体，没有表现出磁序。我们生长了高质量的 CeTa$_7$O$_{19}$单晶，并研究了低温下的磁化率、比热和热导率。直流磁化率和磁化强度揭示了其有效自旋-1/2的性质、易轴各向异性和反铁磁自旋耦合。超低温交流磁化率和比热数据表明，在20 mK以下没有出现任何相变。 零磁场下的超低温热导率 ($\kappa$) 显示出一个非零的剩余项 $\kappa_0/T =$ 0.0056 W/K$^2$m。尽管 $\kappa$ 的磁场依赖性较弱，但 14 T 的热导率显示出本质上的零剩余项。 所有这些结果表明可能存在一种量子自旋液体的基态。 显示英文摘要

摘要： CeTa$_7$O$_{19}$ is a recently found two-dimensional triangular lattice antiferromagnet without showing magnetic order. We grew high-quality CeTa$_7$O$_{19}$ single crystals and studied the low-temperature magnetic susceptibility, specific heat and thermal conductivity. The dc magnetic susceptibility and magnetization reveal its nature of effective spin-1/2, easy axis anisotropy, and antiferromagnetic spin coupling. The ultralow-temperature ac susceptibility and specific heat data indicate the absence of any phase transition down to 20 mK. The ultralow-temperature thermal conductivity ($\kappa$) at zero magnetic field exhibits a non-zero residual term $\kappa_0/T =$ 0.0056 W/K$^2$m. Although the magnetic field dependence of $\kappa$ is rather weak, the 14 T thermal conductivity shows an essential zero residual term. All these results point to a possible ground state of quantum spin liquid.