Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 71: New concepts and new materials
HL 71.4: Vortrag
Donnerstag, 19. März 2015, 11:00–11:15, EW 201
Full two-dimensional band-mapping of Ni-intercalated TiS2 by momentum microscopy — •Shigemasa Suga1,2, Christian Tusche1, Yuichiro Matsushgita1, Martin Ellguth1, Akinori Irizawa2, and Jürgen Kirschner1,3 — 1Max-Planck-Institute of Microstructure Physics, Weinberg 2, Halle 06120, Germany — 2Institute of Scientific & Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan — 3Institut für Physik, Martin-Luther-Universität, Halle, Germany
Atom intercalation into the van der Waals gap of a layered semiconductor TiS2 can effectively modify its electronic properties in the bulk and surface. In order to probe the changes of its surface electronic structure on Ni intercalation, we have performed high-resolution and simultaneous two-dimensional photoelectron spectroscopy of Ni1/3TiS2 by use of a momentum microscope. Full (kx,ky) band dispersions are revealed up to 2.0 Å-1. Small electron Fermi surfaces (FSs) with noticeable dispersion observed near the M points in TiS2 became much stronger in Ni1/3TiS2, in which a very small hole FS pocket with clear dispersion is additionally observed near Γ point. Detailed new experimental results are compared with first principles theoretical band calculations. Differences between these materials are dominated by the contribution of the Ni 3d states of the surface Ni atoms positioned at the C3v site, being different from its D3d site beneath the surface. The use of a momentum microscope is demonstrated to be inevitable for clarifying detailed electronic structures of many solids under hot debates. M.E. acknowledges support by the BMBF (05K12EF1).