# Strong energy-momentum dispersion of phonon-dressed carriers in the lightly doped band insulator SrTiO$3$ - Condensed Matter > Strongly Correlated Electrons

Strong energy-momentum dispersion of phonon-dressed carriers in the lightly doped band insulator SrTiO$3$ - Condensed Matter > Strongly Correlated Electrons - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: Much progress has been made recently in the study of the effects ofelectron-phonon el-ph coupling in doped insulators using angle resolvedphotoemission ARPES, yielding evidence for the dominant role of el-phinteractions in underdoped cuprates. As these studies have been limited todoped Mott insulators, the important question arises how this compares withdoped band insulators where similar el-ph couplings should be at work. Thearchetypical case is the perovskite SrTiO$3$ STO, well known for its giantdielectric constant of 10000 at low temperature, exceeding that ofLa$2$CuO$4$ by a factor of 500. Based on this fact, it has been suggestedthat doped STO should be the archetypical bipolaron superconductor. Here wereport an ARPES study from high-quality surfaces of lightly doped SrTiO$3$.Comparing to lightly doped Mott insulators, we find the signatures of onlymoderate electron-phonon coupling: a dispersion anomaly associated with the lowfrequency optical phonon with a $\lambda-\sim0.3$ and an overall bandwidthrenormalization suggesting an overall $\lambda-\sim0.7$ coming from the higherfrequency phonons. Further, we find no clear signatures of the large pseudogapor small polaron phenomena. These findings demonstrate that a large dielectricconstant itself is not a good indicator of el-ph coupling and highlight theunusually strong effects of the el-ph coupling in doped Mott insulators.

Autor: W. Meevasana, X. J. Zhou, B. Moritz, C-C. Chen, R.H. He, S.-I. Fujimori, D.H. Lu, S.-K. Mo, R.G. Moore, F. Baumberger, T.P. Dever

Fuente: https://arxiv.org/