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DS: Fachverband Dünne Schichten
DS 18: Transport: Topological Semimetals 1 (jointly with MA/TT)
DS 18.6: Vortrag
Dienstag, 21. März 2017, 11:00–11:15, HSZ 201
Observation of Topological Surface States and Strong Electron/hole Imbalance in an Extreme Magnetoresistance Semimetal — •Niels Bernhard Michael Schröter1, Juan Jiang1,2,3,4, Shu-Chun Wu5, Nitesh Kumar5, Chandra Shekhar5, Han Peng1, Xiang Xu6, Cheng Chen1, Haifung Yang7, Chan Hwang4, Sung-Kwan Mo3, Zhongkai Liu2, Lexiang Yang6, Claudia Felser5, Binghai Yan5, and Yulin Chen1,2,6 — 1University of Oxford, Oxford, UK — 2ShanghaiTech University, Shanghai, P. R. China — 3Advanced Light Source, Berkeley, USA — 4Pohang Accelerator Laboratory, POSTECH, Pohang, Korea — 5Max Planck Institute for Chemical Physics of Solids, Dresden, Germany — 6Tsinghua University, Beijing, P. R. China — 7Chinese Academy of Sciences, Shanghai, P. R. China
The discovery of an extreme magnetoresistance (XMR) in the non-magnetic rare-earth monopnictides LaX (X = P, As, Sb, Bi), a recently proposed new topological semimetal family, has inspired intensive research on the correlation between the XMR and their electronic structures. In this work, using ARPES to investigate the three dimensional band structure of a lanthanum monopnictide, we unraveled its topologically non-trivial nature with the observation of multiple topological surface Dirac fermions, as supported by our ab-initio calculations. Furthermore, we observed substantial imbalance between the volumes of electron and hole pockets, which rules out the electron-hole compensation as the primary cause of the XMR, putting strong constraints on future theoretical investigations.