著者 | Ilya Belopolski, Su-Yang Xu, Yukiaki Ishida, Xingchen Pan, Peng Yu, Daniel S. Sanchez, Hao Zheng, Madhab Neupane, Nasser Alidoust, Guoqing Chang, Tay-Rong Chang, Yun Wu, Guang Bian, Shin-Ming Huang, Chi-Cheng Lee, Daixiang Mou, Lunan Huang, You Song, Baigeng Wang, Guanghou Wang, Yao-Wen Yeh, Nan Yao, Julien E. Rault, Patrick Le Fèvre, François Bertran, Horng-Tay Jeng, Takeshi Kondo, Adam Kaminski, Hsin Lin, Zheng Liu, Fengqi Song, Shik Shin, and M. Zahid Hasan |
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摘要 | It has recently been proposed that electronic band structures in crystals can give rise to a previously overlooked type of Weyl fermion, which violates Lorentz invariance and, consequently, is forbidden in particle physics. It was further predicted that MoxW1−xTe2 may realize such a type-II Weyl fermion. Here, we first show theoretically that it is crucial to access the band structure above the Fermi level ɛF to show a Weyl semimetal in MoxW1−xTe2. Then, we study MoxW1−xTe2 by pump-probe ARPES and we directly access the band structure >0.2 eV above ɛF in experiment. By comparing our results with ab initio calculations, we conclude that we directly observe the surface state containing the topological Fermi arc. We propose that a future study of MoxW1−xTe2 by pump-probe ARPES may directly pinpoint the Fermi arc. Our work sets the stage for the experimental discovery of the first type-II Weyl semimetal in MoxW1−xTe2. |
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