Non-Stoichiometry Effects on the Extreme Magnetoresistance in Weyl Semimetal WTe$_{2}$
Ji-Xiang Gong1,2, Jun Yang1, Min Ge2**, Yong-Jian Wang1, Dan-Dan Liang1, Lei Luo1, Xiu Yan1, Wei-Li Zhen1, Shi-Rui Weng1, Li Pi1,2, Chang-Jin Zhang1,3**, Wen-Ka Zhu1**
1High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031 2Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026 3Institute of Physical Science and Information Technology, Anhui University, Hefei 230601
Abstract：Non-stoichiometry effect on the extreme magnetoresistance is systematically investigated for the Weyl semimetal WTe$_{2}$. Magnetoresistance and Hall resistivity are measured for the as-grown samples with a slight difference in Te vacancies and the annealed samples with increased Te vacancies. The fits to a two-band model show that the magnetoresistance is strongly dependent on the residual resistivity ratio (i.e., the degree of non-stoichiometry), which is eventually understood in terms of electron doping that not only breaks the balance between electron-type and hole-type carrier densities, but also reduces the average carrier mobility. Thus the compensation effect and ultrahigh mobility are probably the main driving force of the extreme magnetoresistance in WTe$_{2}$.
2018, Vol. 35 
