Fermi arc electronic structure and Chern numbers in the type-II Weyl semimetal candidate ${\mathrm{Mo}}_x{\mathrm{W}}_{1-x}{\mathrm{Te}}_2$

Journal Article · Mon Aug 15 04:00:00 EDT 2016 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.94.085127· OSTI ID:1342950

Belopolski, Ilya; Xu, Su-Yang; Ishida, Yukiaki; Pan, Xingchen; Yu, Peng; Sanchez, Daniel S.; Zheng, Hao; Neupane, Madhab; Alidoust, Nasser; Chang, Guoqing; Chang, Tay-Rong; Wu, Yun; Bian, Guang; Huang, Shin-Ming; Lee, Chi-Cheng; Mou, Daixiang; Huang, Lunan; Song, You; Wang, Baigeng; Wang, Guanghou ; Yeh, Yao-Wen; Yao, Nan; Rault, Julien E.; Le Fèvre, Patrick; Bertran, François; Jeng, Horng-Tay; Kondo, Takeshi; Kaminski, Adam; Lin, Hsin; Liu, Zheng; Song, Fengqi; Shin, Shik; Hasan, M. Zahid

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 Mo _x W _{1 - x} Te ₂ 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 ε F to show a Weyl semimetal in Mo _x W _{1 - x} Te ₂ . Then, we study Mo x W _{1 - x} Te ₂ by pump-probe ARPES and we directly access the band structure > 0.2 eV above ε F 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 Mo _x W _{1 - x} Te ₂ 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 Mo _x W _{1 - x} Te ₂ .

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• DOE Contract Number: FG02-05ER46200; AC02-07CH11358
• OSTI ID: 1342950
• Report Number(s): IS--J 8989
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 8 Vol. 94; ISSN 2469-9950; ISSN PRBMDO
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

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