Large spectral weight transfer in optical conductivity of SrTiO₃ induced by intrinsic vacancies

2012/06/28 by Asmara, Teguh C., Wang, Xiao, Santoso, Iman +11
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Strongly Correlated Electrons (cond-mat.str-el)

paper · doi:10.48550/arxiv.1206.6686

Abstract

The optical conductivity (σ₁) of SrTiO₃ for various vacancies has been systematically studied using a combination of ultraviolet - vacuum ultraviolet (UV-VUV) reflectivity and spectroscopic ellipsometry. For cation (Ti) vacancies, σ₁ shows large spectral weight transfer over a wide range of energy from as high as 35 eV to as low as 0.5 eV and the presence of mid-gap states, suggesting that strong correlations play an important role. While for anion (O) vacancies σ₁ shows changes from 7.4 eV up to 35 eV. These unexpected results can be explained in terms of orbital reconstruction.

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