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arXiv · 0712.1607

Electron-phonon interaction and charge carrier mass enhancement in SrTiO3

J. L. M. van Mechelen·D. van der Marel·C. Grimaldi·A. B. Kuzmenko·N. P. Armitage·N. Reyren·H. Hagemann·I. I. Mazin
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Abstract

We report a comprehensive THz, infrared and optical study of Nb doped SrTiO3 as well as DC conductivity and Hall effect measurements. Our THz spectra at 7K show the presence of a very narrow (<2 meV) Drude peak, the spectral weight of which shows approximately a factor of three enhancement of the band mass for all carrier concentrations. The missing spectral weight is regained in a broad 'mid-infrared' band which originates from electron-phonon coupling. We find no evidence of a particularly large electron-phonon coupling that would result in small polaron formation. Analysis of the results yields an electron-phonon coupling parameter of an intermediate strength, $α\approx 4$.

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J. L. M. van Mechelen, D. van der Marel, C. Grimaldi, A. B. Kuzmenko, N. P. Armitage, N. Reyren, H. Hagemann, I. I. Mazin. 2007-12-10. Electron-phonon interaction and charge carrier mass enhancement in SrTiO3. https://doi.org/10.1103/physrevlett.100.226403

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