Dresden 2017 – scientific programme
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O: Fachverband Oberflächenphysik
O 79: Electronic Structure of Surfaces: Spectroscopy, Surface States I
O 79.10: Talk
Wednesday, March 22, 2017, 17:30–17:45, WIL C307
Surface states of transition-metal delafossite oxides — •Veronika Sunko1,2, Helge Rosner2, Pallavi Kushwaha2, Lewis Bawden1, Oliver J. Clark1, Jonathon M. Riley2,3, Deepa Kasinathan2, Maurits W. Haverkort2, Andrew P. Mackenzie1,2, and Philip D.C. King2 — 1SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, UK — 2MPI-CPfS, Nöthnitzer Straße 40, 01217 Dresden, Germany — 3Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK
Delafossite oxides have recently attracted considerable attention because of their fascinating transport properties[1]. PdCoO2 and PtCoO2 are the most conductive oxides known at room temperature, with resistivities comparable to those of silver, copper and gold[2, 3]. This high conductivity is attributed to a single broad band crossing the Fermi level[3]. However, due to the polarity of the structure the electronic properties at the surfaces can be very different to those of the bulk[4]. We use angle resolved photoemission (ARPES) to show that the CoO2 terminated surfaces of (Pd,Pt)CoO2 do host a set of states which do not appear in the bulk, with much higher masses and stronger interactions. Comparing ARPES with density functional theory and model tight-binding calculations, we investigate the origin of these states, paying special attention to the role of the spin-orbit coupling.
[1] Moll et al., Science 351 (2016) 6277, Kikugawa et al., Nature Commun. 7 (2016) 10903 [2] Hicks et al., PRL 109 (2012) 116401 [3] Kushwaha et al., Science Adv. 1 (2015) e1500692 [4] Kim et al., PRB 80 (2009) 035116, Noh et al., PRL 102 (2009) 256404