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arXiv · 1004.0042

Evidence for a correlated insulator to antiferromagnetic metal transition in CrN

P. A. Bhobe·A. Chainani·M. Taguchi·T. Takeuchi·R. Eguchi·M. Matsunami·K. Ishizaka·Y. Takata·M. Oura·Y. Senba·H. Ohashi·Y. Nishino·M. Yabashi·K. Tamasaku·T. Ishikawa·K. Takenaka·H. Takagi·S. Shin
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Abstract

We investigate the electronic structure of Chromium Nitride (CrN) across the first-order magneto-structural transition at T_N ~ 286 K. Resonant photoemission spectroscopy shows a gap in the 3d partial density of states at the Fermi level and an On-site Coulomb energy U ~ 4.5 eV, indicating strong electron-electron correlations. Bulk-sensitive high resolution (6 meV) laser photoemission reveals a clear Fermi edge indicating an antiferromagnetic metal below T_N. Hard x-ray Cr 2p core-level spectra show T-dependent changes across T_N which originate from screening due to coherent states as substantiated by cluster model calculations using the experimentally observed U. The electrical resistivity confirms an insulator above T_N (E_g ~ 70 meV) which becomes a disordered metal below T_N. The results indicate CrN transforms from a correlated insulator to an antiferromagnetic metal, coupled to the magneto-structural transition.

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P. A. Bhobe, A. Chainani, M. Taguchi, T. Takeuchi, R. Eguchi, M. Matsunami, K. Ishizaka, Y. Takata, M. Oura, Y. Senba, H. Ohashi, Y. Nishino, M. Yabashi, K. Tamasaku, T. Ishikawa, K. Takenaka, H. Takagi, S. Shin. 2010-04-01. Evidence for a correlated insulator to antiferromagnetic metal transition in CrN. https://doi.org/10.1103/physrevlett.104.236404

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