Electron–phonon coupling in Nb-doped SrTiO3 single crystal

• Published in: Journal of physics. Condensed matter Vol. 18; no. 8; pp. 2553 - 2561
• Main Authors: Bi, C Z, Ma, J Y, Yan, J, Fang, X, Zhao, B R, Yao, D Z, Qiu, X G
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.03.2006; Institute of Physics
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states; Exact sciences and technology; Infrared and raman spectra and scattering; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other nonmetallic inorganics; Physics; Polarons and electron-phonon interactions; Monocrystals; Reflection spectrum; Drude model; Line splitting; Phonon mode; Strontium titanates; Plasmons; Niobium additions; Electron-phonon interactions; Infrared spectra; Phonon-plasmon interactions
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/18/8/017

Near normal incident infrared reflectivity spectra of (001) SrTi1 xNbxO3 single crystal have been measured at different temperatures in the frequency region between 100 and 6000 cm 1. The optical parameters of phonons and plasmons are obtained on the basis of the double-damping extended Drude model. The lowest frequency phonon mode at 175 cm 1 softens with decreasing temperature, and the plasmon frequency triples when the temperature decreases from 300 to 10 K. Extra absorption near the highest frequency longitudinal phonon mode shows that the effect of the polarons should be taken into account in addition to the plasmon-phonon coupling. The splitting of the last high reflectivity band, the temperature dependence of the 615 cm 1 structure and the appearance of a new weak peak-like defect mode provide evidence for the existence of small polarons.