Wang Yaojia, Wang Lizheng, Liu Xiaowei, Wu Heng, Wang Pengfei, Yan Dayu, Cheng Bin, Shi Youguo, Watanabe Kenji, Taniguchi Takashi, Liang Shi-Jun, Miao Feng
National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China.
Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China.
Nano Lett. 2019 Jun 12;19(6):3969-3975. doi: 10.1021/acs.nanolett.9b01275. Epub 2019 May 15.
Since the discovery of extremely large nonsaturating magnetoresistance (MR) in WTe, much effort has been devoted to understanding the underlying mechanism, which is still under debate. Here, we explicitly identify the dominant physical origin of the large nonsaturating MR through in situ tuning of the magneto-transport properties in thin WTe film. With an electrostatic doping approach, we observed a nonmonotonic gate dependence of the MR. The MR reaches a maximum (10600%) in thin WTe film at certain gate voltage where electron and hole concentrations are balanced, indicating that the charge compensation is the dominant mechanism of the observed large MR. Besides, we show that the temperature-dependent magnetoresistance exhibits similar tendency with the carrier mobility when the charge compensation is retained, revealing that distinct scattering mechanisms may be at play for the temperature dependence of magneto-transport properties. Our work would be helpful for understanding mechanism of the large MR in other nonmagnetic materials and offers an avenue for achieving large MR in the nonmagnetic materials with electron-hole pockets.
自从在WTe₂中发现极大的非饱和磁电阻（MR）以来，人们投入了大量精力来理解其潜在机制，而该机制仍存在争议。在此，我们通过对WTe₂薄膜磁输运性质的原位调控，明确确定了大非饱和磁电阻的主要物理起源。采用静电掺杂方法，我们观察到磁电阻对栅极的非单调依赖性。在一定的栅极电压下，当电子和空穴浓度达到平衡时，WTe₂薄膜中的磁电阻达到最大值（10600%），这表明电荷补偿是所观察到的大磁电阻的主导机制。此外，我们表明，当保持电荷补偿时，与温度相关的磁电阻与载流子迁移率呈现相似的趋势，这揭示了磁输运性质的温度依赖性可能存在不同类型的散射机制。我们的工作将有助于理解其他非磁性材料中大磁电阻的机制，并为在具有电子 - 空穴口袋的非磁性材料中实现大磁电阻提供一条途径。
