Regensburg 2013 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 38: Correlated Electrons: Metal-Insulator Transition 1
TT 38.5: Talk
Wednesday, March 13, 2013, 10:30–10:45, H20
Electronic structure of Nb0.75O0.75 — •Anna Efimenko1,2, Nils Hollmann1, Katharina Höfer1, Jonas Weinen1, Alexander C. Komarek1, Zhiwei Hu1, A.Agung Nugroho3, Hui-Huang Hsieh4, Hong-Ji Lin4, Chien-Te Chen4, Aurora Diana Rata1, and Liu Hao Tjeng1 — 1Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany — 2II.Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, 50937 Köln, Germany — 3Institut Teknologi Bandung, Jl. Ganesa 10 Bandung, 40132, Indonesia — 4National Synchrotron Radiation Research Center (NSRRC), 101 Hsin-Ann Road, 30077 Hsinchu, Taiwan
We report on our angle-resolved photoemission (ARPES) study of Nb0.75O0.75 single crystals. NbO crystallizes in a rocksalt structure with 25% of ordered vacancies on both Nb - and O - sublattices. We compare our experimental data with the electronic structure calculated by density functional theory. Experimentally obtained bands are assigned to bulk and plausible surface electronic states. The effect of the so called "ordered vacancies" formation on the electronic structure in this compound is discussed. Our results demonstrate the shortcomings of the ionic model for Nb0.75O0.75 and the importance of metal-metal bonds for the structural stability. We provide insight into the bonding of Nb and O by constructing the topology of the orbitals from projected Wannier functions.