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国际合作中心报告
 
题目: Magnetoresistance from Fermi Surface Topology
时间: 2019年05月21日 09:00
地点: 物理所M253会议室
报告人: Dr. Quansheng Wu

Swiss federal Institute of Technology in Lausanne, Switzerland 

Abstract:

Extremely large non-saturating magnetoresistance has recently been reported for a large number of both topologically trivial and non-trivial materials. Different mechanisms have been proposed to explain the observed magnetotransport properties, yet without arriving to definitive conclusions or portraying a global picture. In this work, we investigate the transverse magnetoresistance of materials by combining the Fermi surfaces calculated from first principles with the Boltzmann transport theory approach relying on the semiclassical model and the relaxation time approximation. We first consider a series of simple model Fermi surfaces to provide a didactic introduction into the charge-carrier compensation and open-orbit mechanisms leading to non-saturating magnetoresistance. We then address in detail magnetotransport in three representative materials: (i) copper, a prototypical nearly free-electron metal characterized by the open Fermi surface that results in an intricate angular magnetoresistance, (ii) bismuth, a topologically trivial semimetal in which very large magnetoresistance is known to result from charge-carrier compensation, and (iii) tungsten diphosphide WP2, a recently discovered type-II Weyl semimetal that holds the record of magnetoresistance in compounds. (iv) a Dirac nodal line semimetal ZrSiS.  In all three cases our calculations show excellent agreement with both the field dependence of magnetoresistance and its anisotropy measured at low temperatures. Furthermore, the calculations allow for a full interpretation of the observed features in terms of the Fermi surface topology. These results will help addressing a number of outstanding questions, such as the role of the topological phase in the pronounced large non-saturating magnetoresistance observed in topological materials.

Brief CV of Dr. Quansheng Wu: 

Dr. QuanSheng Wu received his BS degree from Beijing Normal University in 2008 and Ph.D. Degree from the University of Chinese Academy of Science in 2013. Now, he works in EPFL as a postdoctoral scientist. One of his research interests lies in the studies of novel topological materials, including looking for novel topological phase, finding suitable candidates as well as studying electronic structures and transport properties of topological materials. The other one is developing open-source software WannierTools, which is an ideal software for topological material investigation. 

References:

1. Magnetoresistance from Fermi Surface Topology, ShengNan Zhang, QuanSheng Wu, Yi Liu, Oleg V. Yazyev PhysRevB.99.035142 (2019).

2. Highly anisotropic interlayer magnetoresistance in ZrSiS nodal-line Dirac semimetal  M. Novak, S. N. Zhang, F. Orbanic, N. Biliskov, G. Eguchi, S. Paschen, A. Kimura, X. X. Wang, T. Osada, K. Uchida, M. Sato, Q. S. Wu, O. V. Yazyev, I. Kokanovic arXiv:1904.09933.

联系人:傅琦(82649469)


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