论文标题
二维依赖性类型-II Weyl半学状态Mo $ $ _ {0.25} $ W $ _ {0.75} $ TE $ _ {2} $
Dimensionality-dependent type-II Weyl semimetal state in Mo$_{0.25}$W$_{0.75}$Te$_{2}$
论文作者
论文摘要
II型Weyl半法（WSM）中的Weyl节点和费米弧已导致许多异国的运输现象。最近，Mo $ _ {0.25} $ W $ _ {0.75} $ te $ _ {2} $已确定为位于费米级附近的Weyl点的类型-II WSM，该级别的Weyl点可以通过电气运输测量结果来研究其有趣的频带结构。 Here, by selecting a special sample with the thickness gradient across two- (2D) and three-dimensional (3D) regime, we show strong evidences that Mo$_{0.25}$W$_{0.75}$Te$_{2}$ is a type-II Weyl semimetal by observing the following two dimensionality-dependent transport features: 1) A chiral-anomaly-induced各向异性磁电导性增强，与平面磁场的平方成正比（b $ _ {in} $$^{2} $）; 2）额外的量子振荡，依赖厚度依赖性相移。我们的理论计算表明，观察到的量子振荡源自Mo $ $ $ $ _ {0.25} $ W $ _ {0.75} $ te $ te $ _ {2} $的独特带结构，源自类似Weyl-Orbit的场景。原位维度调整的运输实验为搜索II型WSM的新策略提供了新的策略。
Weyl nodes and Fermi arcs in type-II Weyl semimetals (WSMs) have led to lots of exotic transport phenomena. Recently, Mo$_{0.25}$W$_{0.75}$Te$_{2}$ has been established as a type-II WSM with Weyl points located near Fermi level, which offers an opportunity to study its intriguing band structure by electrical transport measurements. Here, by selecting a special sample with the thickness gradient across two- (2D) and three-dimensional (3D) regime, we show strong evidences that Mo$_{0.25}$W$_{0.75}$Te$_{2}$ is a type-II Weyl semimetal by observing the following two dimensionality-dependent transport features: 1) A chiral-anomaly-induced anisotropic magneto-conductivity enhancement, proportional to the square of in-plane magnetic field (B$_{in}$$^{2}$); 2) An additional quantum oscillation with thickness-dependent phase shift. Our theoretical calculations show that the observed quantum oscillation originates from a Weyl-orbit-like scenario due to the unique band structure of Mo$_{0.25}$W$_{0.75}$Te$_{2}$. The in situ dimensionality-tuned transport experiment offers a new strategy to search for type-II WSMs.
