Nonadiabatic small polaron tunneling conduction in reduced Cr-doped SrTiO3−δ thin films

Abstract

We investigated the electrical conduction and dielectric relaxation of reduced Cr-doped SrTiO3−δ thin films. The electrical conduction behavior indicates the formation of small polarons in oxygen deficient Cr-doped SrTiO3−δ thin films. The associated dielectric relaxation further indicates nonadiabatic small polaron tunneling conduction. A strong electron-phonon interaction is identified based on the large polaron coupling constant, α≈28(α⪢4).