Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 62: Poster Wednesday: Topology and Symmetry-Protected Materials

O 62.7: Poster

Mittwoch, 3. April 2019, 17:45–20:00, Poster B1

Topological surface states in semi-metallic Tm monochalcogenides — •Chul-Hee Min¹, Chang Jong Kang², Katharina Kissner¹, Hendrik Bentmann¹, Dong-Choon Ryu³, Woo Jae Choi⁴, Yong-Seong Kwon⁴, Volodymyr Zabolotnyy¹, Vladimir Hinkov¹, Byung-Il Min³, and Friedrich Reinert¹ — ¹Universität Würzburg, EP7, Würzburg, Germany — ²Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08856, USA — ³Department of Physics, PCTP, POSTECH, Pohang 37673, Korea — ⁴Department of Emerging Materials Science, DGIST, Daegu 42988, Republic of Korea

Topological surface states with strongly localized 4f character have not been clearly identified in experiments yet. Analogous to hypothetically topological non-insulating rare earth materials, e.g. g-SmS and SmO [1,2], we propose Thulium monochalcogenides, TmSe_1−xTe_x, to be a very promising candidate to realize even topological Dirac or Weyl semimetals. The compounds having simple fcc structure show mixed valency overall, and insulating behaviors in resistivity. By means of ARPES, their Fermi surface maps and constant energy cuts will be present, which show a good agreement with our DFT calculation results. If the energy positions of 4f bands of Tm in DFT results can be renormalized with factor of 0.1, we can identify most of theoretical Fermi surface features, including the 4f surface states.

[1] D. Kasinathan, K. Koepernik, L. H. Tjeng, and M. Haverkort, Phys. Rev. B, 91 195127 (2015). [2] C.-J. Kang, H.-C. Choi, Kyoo Kim, and B. I. Min, Phys. Rev. Lett., 114, 166404 (2015).