  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 intensity of ABJ anomaly, along a- and b-axis of WTe$_{1.98}$ are
0.030 and 0.051 T$^{-2}$ at 2 K, respectively. We found that
temperature-sensitive ABJ anomaly is attributed to topological phase transition
from type-II Weyl semimetal to trivial semimetal, which is verified by
first-principles calculation using experimentally determined lattice parameters
at different temperatures. Theoretical electrical transport study reveals that
observation of ansotropic ABJ both along a- and b-axis in WTe$_{1.98}$ is
attributed to electrical transport in the quasi-classical regime. Our work may
suggest that electron-doped WTe$_2$ is an ideal playground to explore the novel
properties in type-II Weyl semimetals.

Materials Science