Extreme magnetoresistance in the topologically trivial lanthanum monopnictide LaAs
Extreme magnetoresistance in the topologically trivial lanthanum monopnictide LaAs
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DOI：
10.1103/physrevb.96.235128
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发表时间：
2017-12
影响因子：
3.7
通讯作者：
Hyunsoo Yang;T. Nummy;H. Li;S. Jaszewski;M. Abramchuk;D. Dessau;F. Tafti
中科院分区：
文献类型：
--
作者：
Hyunsoo Yang;T. Nummy;H. Li;S. Jaszewski;M. Abramchuk;D. Dessau;F. Tafti
镧系双金属氧化物LaBi和LaSb由于具有不寻常的极磁阻效应而引起了人们的广泛关注。对此有两类解释：非平凡拓扑的存在，以及电子和空穴密度之间的补偿。在这里，通过合成该家族的新成员LaAs，并进行输运测量、角分辨光电子能谱（ARPES）和密度泛函理论（DFT）计算，我们表明：（a）LaAs保留了XMR效应的所有定性特征，但与LaSb和LaBi相比，其量级显著降低，（B）在LaAs中不存在能带反转或狄拉克锥表明拓扑结构对XMR是无关紧要的，（c）电子和空穴载流子的相等数目表明XMR需要补偿，但不能解释其大小，（d）LaAs中电子和空穴迁移率的比值与LaSb和LaBi相比有很大的不同。我们认为，补偿是负责的XMR配置文件和迁移率失配约束的XMR的大小。
The family of binary Lanthanum monopnictides, LaBi and LaSb, have attracted a great deal of attention as they display an unusual extreme magnetoresistance (XMR) that is not well understood. Two classes of explanations have been raised for this: the presence of non-trivial topology, and the compensation between electron and hole densities. Here, by synthesizing a new member of the family, LaAs, and performing transport measurements, Angle Resolved Photoemission Spectroscopy (ARPES), and Density Functional Theory (DFT) calculations, we show that (a) LaAs retains all qualitative features characteristic of the XMR effect but with a siginificant reduction in magnitude compared to LaSb and LaBi, (b) the absence of a band inversion or a Dirac cone in LaAs indicates that topology is insignificant to XMR, (c) the equal number of electron and hole carriers indicates that compensation is necessary for XMR but does not explain its magnitude, and (d) the ratio of electron and hole mobilities is much different in LaAs compared to LaSb and LaBi. We argue that the compensation is responsible for the XMR profile and the mobility mismatch constrains the magnitude of XMR.