论文标题
kitaev材料的现场引起的相变
Field-induced phase transitions of the Kitaev material $α$-RuCl$_3$ probed by thermal expansion and magnetostriction
论文作者
论文摘要
高分辨率的热膨胀和磁截面测量值在$α$ -rucl $ _3 $的单晶上进行，在与RU-RU键平行的磁场中进行。长度变化是在垂直于蜂窝平面的方向上测量的。我们的数据显示了在临界场处的场诱导的相变的清晰热力学特性$μ_0H_{C1} = 7.8（2）$ t，其中抗fiferromagnetic Zigzag顺序被抑制。在较高的田地上，磁曲系数中的扭结信号在$μ_0H__{C2} \ of 11 $ t中进行了额外的相变。提取的grüneisen参数显示了典型的量子标志，该标志是$ h_ {c1} $附近的量子标志，但也显示出$ h_ {c1} $ h_ {c1} $ h_ {c1} $ a的nomalous行为。我们将实验数据与线性自旋波的计算进行比较，该计算在半经典限制下采用最小的Kitaev-Heisenberg模型进行了比较。大多数显着特征是彼此一致的，但是，在我们的建模中无法解释高于$ h_ {c1} $的高场区域的特殊功能，因此暗示了真正的量子性质。我们为$α$ -rucl $ _3 $构建一个相图，显示了沿RU-RU债券的平面场引起的两个低温过渡。
High-resolution thermal expansion and magnetostriction measurements were performed on single crystals of $α$-RuCl$_3$ in magnetic fields applied parallel to the Ru-Ru bonds. The length changes were measured in the direction perpendicular to the honeycomb planes. Our data show clear thermodynamic characteristics for the field-induced phase transition at the critical field $μ_0H_{c1} = 7.8(2)$ T where the antiferromagnetic zigzag order is suppressed. At higher fields, a kink in the magnetostriction coefficient signals an additional phase transition around $μ_0H_{c2} \approx 11$ T. The extracted Grüneisen parameter shows typical hallmarks for quantum criticality near $H_{c1}$, but also displays anomalous behavior above $H_{c1}$. We compare our experimental data with linear spin-wave calculations employing a minimal Kitaev-Heisenberg model in the semiclassical limit. Most of the salient features are in agreement with each other, however, the peculiar features in the high-field region above $H_{c1}$ cannot be accounted for in our modelling and hence suggest a genuine quantum nature. We construct a phase diagram for $α$-RuCl$_3$ showing two low-temperature transitions induced by an in-plane field along the Ru-Ru bonds.
