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DF: Fachverband Dielektrische Festkörper
DF 11: Small Polarons in LiNbO3
DF 11.2: Vortrag
Mittwoch, 18. März 2015, 09:50–10:10, EB 133C
Density functional theory investigation of iron small bound polarons — •Simone Sanna and Wolf Gero Schmidt — Lehrstuhl für Theoretische Physik, Universität Paderborn
Iron doped lithium niobate is one of the most prominent photorefractive materials and is vastly employed, among others, for holographic data storage and optical filters. The dominant charge transport mechanism initiating photorefractive effect is the bulk photovoltaic effect, which is currently interpreted on the basis of Fe2+/3+ small bound polarons [1]. In this work, we present a quantitative microscopic description of Fe2+/3+ polaronic centers. Spin-polarized density functional theory with Hubbard corrections is employed to investigate the atomic structure around FeLi centers. The theoretical models are compared with available experimental results [2,3], providing clear evidence for the polaronic distortion upon Fe2+/3+ charge transition. The calculated atomic and electronic structures allow for a detailed consideration of the microscopic processes leading to the optical absorption, as well as the extrapolation of data that can be employed in the classic polaronic theory.
[1] O. F. Schirmer et al., Phys. Rev. B 83, 165106 (2011)
[2] T. Vitova et al., J. Appl. Phys. 105, 013524 (2009)
[3] A. Sanson et al., Submitted to Phys. Rev. B (2014)