Electronic structure of Nd_{1鈭?span style='font-style: italic'>x}Y_xMnO₃ from Mn K edge absorption spectroscopy and DFT methods

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• 作者：Padmanabhan Balasubramanian ; Ruchika Yadav ; Harikrishnan S. Nair ; H.M. Tsai ; Y. Joly ; J.F. Lee ; Suja Elizabeth ; B.R. Sekhar ; C.W. Pao ; W.F. Pong
• 关键词：A. Strongly correlated systems ; D. Density of states ; E. X-ray absorption
• 刊名：Solid State Communications
• 出版年：March, 2014
• 年：2014
• 卷：181
• 期：Complete
• 页码：50-53
• 全文大小：421 K

文摘

The electronic structure of Nd_1鈭?em>xY_xMnO₃ (x=0-0.5) is studied using x-ray absorption near-edge structure (XANES) spectroscopy at the Mn K-edge along with the DFT-based LSDA+U and real space cluster calculations. The main edge of the spectra does not show any variation with doping. The pre-edge shows two distinct features which appear well-separated with doping. The intensity of the pre-edge decreases with doping. The theoretical XANES were calculated using real space multiple scattering methods which reproduces the entire experimental spectra at the main edge as well as the pre-edge. Density functional theory calculations are used to obtain the Mn 4p, Mn 3d and O 2p density of states. For x=0, the site-projected density of states at 1.7 eV above Fermi energy shows a singular peak of unoccupied e_g (spin-up) states which is hybridized Mn 4p and O 2p states. For x=0.5, this feature develops at a higher energy and is highly delocalized and overlaps with the 3d spin-down states which changes the pre-edge intensity. The Mn 4p DOS for both compositions, show considerable difference between the individual p_x, p_y and p_z states. For x=0.5, there is a considerable change in the 4p orbital polarization suggesting changes in the Jahn-Teller effect with doping.