近日，以色列魏茨曼科学研究所的Erez Berg及其研究小组取得一项新进展。经过不懈努力，他们揭示量子霍尔体的热传导过程。相关研究成果已于2024年1月3日在国际权威学术期刊《自然》上发表。
该研究团队对体热传导进行了广泛的研究。研究人员利用一种新型的“多终端”短器件（尺寸在10μm尺度上），通过消除边缘模式的贡献，成功地将纵向热导kxxT（由体贡献的部分）与拓扑横向热导kxyT进行了分离。当磁场远离电导平台中心时，体中的局域态成为有效的导热通道（kxxT与温度T成正比），而体仍然保持电绝缘。在第一激发朗道能级中，如v=7/3和v=5/2的分数态，能够以有限的kxxT在整个平台上传导热量。研究人员提出了一个理论模型，该模型确定了局域态是导致有限热传导的原因，这与实验结果定性上是一致的。
据悉，量子霍尔效应是物质拓扑态的一种典型实现。它产生于拓扑结构、相互作用和无序之间微妙的相互作用。这种无序使得在体中形成局域态，使量子霍尔态相对于磁场和载流子密度稳定下来。然而，局部状态的细节及其对输运的贡献仍然超出了大多数实验技术的范围。
附：英文原文
Title: Heat conductance of the quantum Hall bulk
Author: Melcer, Ron Aharon, Gil, Avigail, Paul, Arup Kumar, Tiwari, Priya, Umansky, Vladimir, Heiblum, Moty, Oreg, Yuval, Stern, Ady, Berg, Erez
Issue&Volume: 2024-01-03
Abstract: The quantum Hall effect is a prototypical realization of a topological state of matter. It emerges from a subtle interplay between topology, interactions and disorder. The disorder enables the formation of localized states in the bulk that stabilize the quantum Hall states with respect to the magnetic field and carrier density. Still, the details of the localized states and their contribution to transport remain beyond the reach of most experimental techniques. Here we describe an extensive study of the bulk’s heat conductance. Using a novel ‘multiterminal’ short device (on a scale of 10μm), we separate the longitudinal thermal conductance, kxxT (owing to the bulk’s contribution), from the topological transverse value kxyT by eliminating the contribution of the edge modes. When the magnetic field is tuned away from the conductance plateau centre, the localized states in the bulk conduct heat efficiently (kxxT∝T), whereas the bulk remains electrically insulating. Fractional states in the first excited Landau level, such as the v=7/3 and v=5/2, conduct heat throughout the plateau with a finite kxxT. We propose a theoretical model that identifies the localized states as the cause of the finite heat conductance, agreeing qualitatively with our experimental findings.
DOI: 10.1038/s41586-023-06858-z
Source: https://www.nature.com/articles/s41586-023-06858-z
来源：科学网 小柯机器人