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arXiv 1901.05099cond-mat.str-el
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强关联拓扑Kondo绝缘体中的量子振荡

Quantum oscillations in strongly correlated topological Kondo insulators

Robert Peters, Tsuneya Yoshida, Norio Kawakami

摘要:

近藤拓扑绝缘体SmB 6和YbB 12中的量子振荡现象是最近一个令人困惑的实验发现。在电阻率和磁化强度中观察到的量子振荡通常用费米面的存在来解释。然而,近藤绝缘体没有费米面,因此不应该显示量子振荡。通过在磁场中对拓扑非平凡的近藤绝缘体进行动力学平均场计算,我们分析了关联对窄隙拓扑近藤绝缘体中量子振荡出现的影响,并证明了在拓扑近藤绝缘体中普遍存在的关联和非局域杂化之间的相互作用可以导致可观察到的量子振荡,而不需要费米面。特别是,我们表明,相关性,使它更容易观察量子振荡的磁化强度和电阻率的散装材料。这些量子振荡的基本机制是相关效应和朗道能级非常接近费米能的组合。我们进一步证明,在一个三维系统中的量子振荡可以理解通过分析的物理在二维平面上的动量空间中的杂交方向的磁场消失。我们相信,这种情况是相关的理解观察到的量子振荡的磁转矩SmB6以及振荡的电阻率和磁转矩的YbB12。

英文摘要:

The observation of quantum oscillations in topological Kondo insulators SmB6 and YbB12 is a recent puzzling experimental discovery. Quantum oscillations observed in the resistivity and the magnetization are usually explained by the existence of the Fermi surface. However, Kondo insulators do not have a Fermi surface and thus should not show quantum oscillations. By performing dynamical mean-field calculations for topologically nontrivial Kondo insulators in a magnetic field, we analyze the effect of correlations on the emergence of quantum oscillations in narrow-gap topological Kondo insulators and demonstrate that the interplay between correlations and nonlocal hybridization, ubiquitously occurring in topological Kondo insulators, can lead to observable quantum oscillations without the necessity of a Fermi surface. Particularly, we show that correlations make it easier to observe quantum oscillations in the magnetization and the resistivity of the bulk material. The fundamental mechanism for these quantum oscillations is a combination of correlation effects and Landau levels coming very close to the Fermi energy. We furthermore demonstrate that quantum oscillations in a three-dimensional system can be understood by analyzing the physics on the two-dimensional planes in the momentum space for which the hybridization in direction of the magnetic field vanishes. We believe that this scenario is relevant to understanding the observation of quantum oscillations in the magnetic torque for SmB6 as well as oscillations in the resistivity and the magnetic torque of YbB12.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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