Time-reversal symmetry broken by charge order in CsV3Sb5
Time-reversal symmetry broken by charge order in CsV3Sb5
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CsV_3Sb_5的时间反演对称性被电荷序破缺
DOI：
10.1103/physrevresearch.4.023244
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发表时间：
2022-06-27
影响因子：
4.2
通讯作者：
Luetkens, Hubertus
中科院分区：
文献类型：
--
作者：
Khasanov, Rustem;Das, Debarchan;Luetkens, Hubertus
最近发现的钒基可果美金属AV（3）Sb（5）（A = K，Rb，Cs）在低温下表现出超导性，在高温下表现出电荷密度波（CDW）序。在这个家庭中的电荷有序状态的一个突出特点是，它打破了时间反演对称性（TRSB），这是连接到基本的能带结构的拓扑性质。在这项工作中，零场和高场μ子自旋旋转/弛豫的强大组合被用来研究CsV 3Sb 5中电荷序的TRSB的签名，以及其各向异性特征。通过跟踪μ子自旋极化的面内和面外分量的温度演化，在T-TRSB = T-CDW接近或等于95 K以下，观察到μ子自旋系综感测的内场宽度的增强。在T* 低于或等于30 K时，检测到内场宽度的额外增加，伴随着μ子位置处的局部场方向从ab平面到c轴的变化。值得注意的是，这两个步骤的功能变得非常明显时，施加磁场的8 T沿沿着晶体学c轴，从而表明在CDW过渡的电子响应的场诱导增强。这些结果表明CsV 3Sb 5中的TRSB按电荷顺序具有类似或等于95 K的起始，随后是低于类似或等于30 K的增强的电子响应。所观察到的两步过渡的不同的电荷顺序的不稳定性，其中，根据密度泛函理论计算的框架内进行了讨论，近简并的能量。
The recently discovered vanadium-based kagome metals AV(3)Sb(5) (A = K, Rb, Cs) exhibit superconductivity at low temperatures and charge density wave (CDW) order at high temperatures. A prominent feature of the charge ordered state in this family is that it breaks time-reversal symmetry (TRSB), which is connected to the underlying topological nature of the band structure. In this work, a powerful combination of zero-field and high-field muonspin rotation/relaxation is used to study the signatures of TRSB of the charge order in CsV3Sb5, as well as its anisotropic character. By tracking the temperature evolution of the in-plane and out-of-plane components of the muon-spin polarization, an enhancement of the internal field width sensed by the muon-spin ensemble was observed below T-TRSB = T-CDW similar or equal to 95 K. Additional increase of the internal field width, accompanied by a change of the local field direction at the muon site from the ab plane to the c axis, was detected below T* similar or equal to 30 K. Remarkably, this two-step feature becomes well pronounced when a magnetic field of 8 T is applied along the crystallographic c axis, thus indicating a field-induced enhancement of the electronic response at the CDW transition. These results point to a TRSB in CsV3Sb5 by charge order with an onset of similar or equal to 95 K, followed by an enhanced electronic response below similar or equal to 30 K. The observed two-step transition is discussed within the framework of different charge-order instabilities, which, in accordance with density functional theory calculations, are nearly degenerate in energy.