Doping-induced dimensional crossover and thermopower burst in Nb-doped SrTiO3 superlattices
DELUGAS, PIETRO DAVIDE;FILIPPETTI, ALESSIO;FIORENTINI, VINCENZO
2013-01-01
Abstract
Using advanced ab initio calculations, we describe the formation and confinement of a two-dimensional electron gas in short-period (≃4-nm) Nb-doped SrTiO3 superlattices as a function of Nb doping. We predict complete two-dimensional confinement for doping concentrations higher than 70%. In agreement with previous observations, we find a large thermopower enhancement at room temperature. However, this effect is primarily determined by dilution of the mobile charge over a multitude of weakly occupied bands. As a general rule, we conclude that thermopower in similar heterostructures will be more enhanced by weak, rather than tight, spatial confinement.Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.