Separation of electron and hole dynamics in the semimetal LaSb
Separation of electron and hole dynamics in the semimetal LaSb
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DOI：
10.1103/physrevb.96.125112
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发表时间：
2017-09-07
影响因子：
3.7
通讯作者：
Kwok, W. K.
中科院分区：
文献类型：
--
作者：
Han, F.;Xu, J.;Kwok, W. K.
我们报告调查的磁输运在LaSb，它具有极大的磁阻（XMR）。最重要的是，我们证明了电阻率平台可以解释，而不调用拓扑保护。然后，我们根据Shubnikov-de哈斯（SdH）量子振荡测量确定费米表面，并发现与第一性原理计算得出的体费米口袋非常一致。使用半经典理论和实验确定的费米口袋各向异性，我们定量描述的轨道磁电阻，包括它的角度依赖性。我们发现，XMR在LaSb的起源在于它的高迁移率与减少霍尔效应，高迁移率导致强磁场依赖的纵向磁导。与单能带材料不同，当系统具有两个或更多个带（费米口袋），带有电子和空穴载流子时，由霍尔效应产生的附加电导减少，从而揭示了由纵向磁导实现的潜在XMR。随着霍尔效应的减弱，磁阻率仅仅是纵向磁导率的倒数，从而能够区分电子和空穴对XMR的贡献，其随着磁场的强度和取向而变化。这项工作展示了一种方便的方法来分离的动力学的电荷载流子和揭示的起源XMR的多带材料与各向异性费米表面。我们的方法可以很容易地应用到其他XMR材料。
We report investigations on the magnetotransport in LaSb, which exhibits extremely large magnetoresistance (XMR). Foremost, we demonstrate that the resistivity plateau can be explained without invoking topological protection. We then determine the Fermi surface from Shubnikov-de Haas (SdH) quantum oscillation measurements and find good agreement with the bulk Fermi pockets derived from first-principles calculations. Using a semiclassical theory and the experimentally determined Fermi pocket anisotropies, we quantitatively describe the orbital magnetoresistance, including its angle dependence. We show that the origin of XMR in LaSb lies in its high mobility with diminishing Hall effect, where the high mobility leads to a strong magnetic-field dependence of the longitudinal magnetoconductance. Unlike a one-band material, when a system has two or more bands (Fermi pockets) with electron and hole carriers, the added conductance arising from the Hall effect is reduced, hence revealing the latent XMR enabled by the longitudinal magnetoconductance. With diminishing Hall effect, the magnetoresistivity is simply the inverse of the longitudinal magnetoconductivity, enabling the differentiation of the electron and hole contributions to the XMR, which varies with the strength and orientation of the magnetic field. This work demonstrates a convenient way to separate the dynamics of the charge carriers and to uncover the origin of XMR in multiband materials with anisotropic Fermi surfaces. Our approach can be readily applied to other XMR materials.