Quantum oscillations of electrical resistivity in an insulator
Quantum oscillations of electrical resistivity in an insulator
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DOI：
10.1126/science.aap9607
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发表时间：
2018-10
期刊：
影响因子：
56.9
通讯作者：
Z. Xiang;Y. Kasahara;T. Asaba;B. Lawson;C. Tinsman;Lu Chen;K. Sugimoto;S. Kawaguchi;Y. Sato;Gang Li;S. Yao;Yulin Chen;F. Iga;J. Singleton;Y. Matsuda;Lu Li
中科院分区：
文献类型：
--
作者：
Z. Xiang;Y. Kasahara;T. Asaba;B. Lawson;C. Tinsman;Lu Chen;K. Sugimoto;S. Kawaguchi;Y. Sato;Gang Li;S. Yao;Yulin Chen;F. Iga;J. Singleton;Y. Matsuda;Lu Li
绝缘体还是金属？当金属冷却到较低温度并置于外部磁场中时，其电阻率可能会随着磁场大小的变化而振荡。在绝缘材料中看到这些所谓的量子振荡将是非常不寻常的。香等人。在绝缘体YbB12中报告这样的发现(见Ong的观点)。除了电阻率的振荡外，作者还观察到了磁扭矩的振荡。这些结果对旨在解释YbB12绝缘态的理论提出了挑战。科学，这一期第65页；另见第32页在绝缘体YbB12中，电阻率和磁矩都显示出量子振荡，尽管具有不同的有效质量。在金属中，传导电子在费米表面上的轨道运动在磁场中量子化，这表现为电阻率的量子振荡。这种朗道量子化在绝缘体中通常是不存在的。在这里，我们报告了绝缘体中的一个明显的例外--十二硼化YbB12。YbB12的电阻率比金属的电阻率大得多，表现出明显的量子振荡。这些非传统的振荡是由绝缘体引起的，尽管振荡幅度的温度依赖关系遵循具有大有效质量的金属的传统费米液体理论。磁力矩中的量子振荡也被观察到，尽管有效质量较轻。
Insulator or a metal? When a metal is cooled to low temperatures and placed in an external magnetic field, its resistivity may oscillate as the magnitude of the field is varied. Seeing these so-called quantum oscillations in an insulating material would be very unusual. Xiang et al. report such findings in the insulator ytterbium dodecaboride (YbB12) (see the Perspective by Ong). In addition to oscillations in resistivity, the authors observed oscillations in the magnetic torque. The results present a challenge to theories that aim to explain the insulating state of YbB12. Science, this issue p. 65; see also p. 32 In the insulator YbB12, both resistivity and magnetic torque show quantum oscillations, albeit with different effective masses. In metals, orbital motions of conduction electrons on the Fermi surface are quantized in magnetic fields, which is manifested by quantum oscillations in electrical resistivity. This Landau quantization is generally absent in insulators. Here, we report a notable exception in an insulator—ytterbium dodecaboride (YbB12). The resistivity of YbB12, which is of a much larger magnitude than the resistivity in metals, exhibits distinct quantum oscillations. These unconventional oscillations arise from the insulating bulk, even though the temperature dependence of the oscillation amplitude follows the conventional Fermi liquid theory of metals with a large effective mass. Quantum oscillations in the magnetic torque are also observed, albeit with a lighter effective mass.