Signatures of polaronic excitations in quasi-one-dimensional LaTiO3.41

[摘要] The optical properties of quasi-one-dimensional metallic LaTiO3.41 are studied for the polarization along the a and b axes. With decreasing temperature modes appear along both directions suggestive for a phase transition. The broadness of these modes along the conducting axis might be due to the coupling of the phonons to low-energy electronic excitations across an energy gap. We observe a pronounced midinfrared band with a temperature dependence consistent with (interacting) polaron models. The polaronic picture is corroborated by the presence of strong electron-phonon coupling and the temperature dependence of the dc conductivity.

[关键词] OPTICAL CONDUCTIVITY SPECTRA;ELECTRONIC-STRUCTURE;TEMPERATURE-DEPENDENCE;SINGLE-CRYSTAL;TTF-TCNQ;ABSORPTION;BAND;LA2-XSRXNIO4+DELTA;ATTRACTION;CONDUCTORS