Lv Yang-Yang, Li Xiao, Zhang Bin-Bin, Deng W Y, Yao Shu-Hua, Chen Y B, Zhou Jian, Zhang Shan-Tao, Lu Ming-Hui, Zhang Lei, Tian Mingliang, Sheng L, Chen Yan-Feng
1National Laboratory of Solid State Microstructures & Department of Materials Science and Engineering, Nanjing University, Nanjing, Jiangsu 210093, China.
National Laboratory of Solid State Microstructures & Department of Physics, Nanjing University, Nanjing, Jiangsu 210093, China.
Phys Rev Lett. 2017 Mar 3;118(9):096603. doi: 10.1103/PhysRevLett.118.096603.
The asymmetric electron dispersion in type-II Weyl semimetal theoretically hosts anisotropic transport properties. Here, we observe the significant anisotropic Adler-Bell-Jackiw (ABJ) anomaly in the Fermi-level delicately adjusted WTe_{1.98} crystals. Quantitatively, C_{W}, a coefficient representing the intensity of the ABJ anomaly along the a and b axis of WTe_{1.98} are 0.030 and 0.051 T^{-2} at 2 K, respectively. We found that the temperature-sensitive ABJ anomaly is attributed to a topological phase transition from a type-II Weyl semimetal to a trivial semimetal, which is verified by a first-principles calculation using experimentally determined lattice parameters at different temperatures. Theoretical electrical transport study reveals that the observation of an anisotropic ABJ along both the a and b axes in WTe_{1.98} is attributed to electrical transport in the quasiclassical regime. Our work may suggest that electron-doped WTe_{2} is an ideal playground to explore the novel properties in type-II Weyl semimetals.
理论上，II型外尔半金属中的非对称电子色散具有各向异性的输运特性。在此，我们在费米能级经过精细调节的WTe₁.₉₈晶体中观测到了显著的各向异性阿德勒 - 贝尔 - 贾基夫（ABJ）反常。定量而言，代表WTe₁.₉₈沿a轴和b轴ABJ反常强度的系数Cₐ和Cᵦ在2K时分别为0.030和0.051 T⁻²。我们发现，温度敏感的ABJ反常归因于从II型外尔半金属到平凡半金属的拓扑相变，这通过使用不同温度下实验测定的晶格参数进行的第一性原理计算得到了验证。理论电输运研究表明，在WTe₁.₉₈中沿a轴和b轴观测到的各向异性ABJ归因于准经典 regime中的电输运。我们的工作可能表明，电子掺杂的WTe₂是探索II型外尔半金属新特性的理想平台。
