Zeng L-K, Lou R, Wu D-S, Xu Q N, Guo P-J, Kong L-Y, Zhong Y-G, Ma J-Z, Fu B-B, Richard P, Wang P, Liu G T, Lu L, Huang Y-B, Fang C, Sun S-S, Wang Q, Wang L, Shi Y-G, Weng H M, Lei H-C, Liu K, Wang S-C, Qian T, Luo J-L, Ding H
Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing 100872, China.
Phys Rev Lett. 2016 Sep 16;117(12):127204. doi: 10.1103/PhysRevLett.117.127204.
By combining angle-resolved photoemission spectroscopy and quantum oscillation measurements, we performed a comprehensive investigation on the electronic structure of LaSb, which exhibits near-quadratic extremely large magnetoresistance (XMR) without any sign of saturation at magnetic fields as high as 40 T. We clearly resolve one spherical and one intersecting-ellipsoidal hole Fermi surfaces (FSs) at the Brillouin zone (BZ) center Γ and one ellipsoidal electron FS at the BZ boundary X. The hole and electron carriers calculated from the enclosed FS volumes are perfectly compensated, and the carrier compensation is unaffected by temperature. We further reveal that LaSb is topologically trivial but shares many similarities with the Weyl semimetal TaAs family in the bulk electronic structure. Based on these results, we have examined the mechanisms that have been proposed so far to explain the near-quadratic XMR in semimetals.
通过结合角分辨光电子能谱和量子振荡测量，我们对LaSb的电子结构进行了全面研究。LaSb在高达40 T的磁场下表现出近二次方的极大磁电阻（XMR），且没有任何饱和迹象。我们清楚地分辨出在布里渊区（BZ）中心Γ处的一个球形和一个相交椭球形空穴费米面（FSs），以及在BZ边界X处的一个椭球形电子FS。根据封闭FS体积计算出的空穴和电子载流子完全补偿，且载流子补偿不受温度影响。我们进一步揭示，LaSb在拓扑上是平凡的，但在体电子结构上与外尔半金属TaAs族有许多相似之处。基于这些结果，我们研究了迄今为止提出的解释半金属中近二次方XMR的机制。
