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arXiv · 2012.14795

Dimensionality-dependent type-II Weyl semimetal state in Mo$_{0.25}$W$_{0.75}$Te$_{2}$

Peiling Li·Ya Deng·Chuanghan Hsu·Chao Zhu·Jian Cui·Xue Yang·Jiadong Zhou·Yichun Hung·Jie Fan·Zhongqing Ji·Fanming Qu·Jie Shen·Changli Yang·Xiunian Jing·Hsin Lin·Zheng Liu·Li Lu·Guangtong Liu
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Abstract

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.

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Peiling Li, Ya Deng, Chuanghan Hsu, Chao Zhu, Jian Cui, Xue Yang, Jiadong Zhou, Yichun Hung, Jie Fan, Zhongqing Ji, Fanming Qu, Jie Shen, Changli Yang, Xiunian Jing, Hsin Lin, Zheng Liu, Li Lu, Guangtong Liu. 2020-12-29. Dimensionality-dependent type-II Weyl semimetal state in Mo$_{0.25}$W$_{0.75}$Te$_{2}$. https://doi.org/10.1103/physrevb.104.085423

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