[en] 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.
Disciplines :
Physics
Author, co-author :
Delugas, P.
Filippetti, A.
Verstraete, Matthieu ; Université de Liège - ULiège > Département de physique > Physique des matériaux et nanostructures
Pallecchi, I.
Marré, D.
Fiorentini, V.
Language :
English
Title :
Doping-induced dimensional crossover and thermopower burst in Nb-doped SrTiO$_3$ superlattices
Publication date :
2013
Journal title :
Physical Review. B, Condensed Matter and Materials Physics
ISSN :
1098-0121
eISSN :
1550-235X
Publisher :
American Physical Society, Woodbury, United States - New York
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