title: Electric-field-induced soft-mode hardening in SrTiO3 films
abstract: We have studied electric-field-induced Raman scattering in SrTiO3 thin films using an indium-tin-oxide/SrTiO3/SrRuO3 structure grown by pulsed laser deposition. The soft mode polarized along the field becomes Raman active. Experimental data for electric-field-induced hardening of the soft modes and the tuning of the static dielectric constant are in agreement described by the Lyddane-Sachs-Teller formalism. The markedly different behavior of the soft modes in thin films from that in the bulk is explained by the existence of local polar regions.
authors.affiliation: Department of Physics, the Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.initials: IA
authors.lastname: Akimov
authors.initials: AA
authors.lastname: Sirenko
authors.initials: AM
authors.lastname: Clark
authors.initials: J
authors.lastname: Hao
authors.initials: XX
authors.lastname: Xi