Superconducting transition temperatures of Nb-doped SrTiO3

Electrostatic modulation of the electronic properties of Nb-doped SrTiO3 superconducting films

“…3 shows the carrier concentration dependence of T c for the P ϩ state and the PϪ state and that for reduced and Nb doped STO bulk crystals. 7,8 Since the coherence length of superconducting STO is much larger than d, 28 although the change in carrier concentration is induced over a distance , the Cooper pairs experience an average effective interaction through the proximity effect. 29 We thus used the average carrier concentrations in the inset of Fig.…”

“…4,5 Among perovskite oxides, electron doped SrTiO 3 ͑STO͒, e.g., SrTiO 3Ϫx and Nb-doped SrTiO 3 ͑Nb-STO͒, display superconductivity for carrier concentrations between about 1ϫ10 19 and 10 21 cm Ϫ3 . [6][7][8] The critical temperature T c depends on the carrier concentration and reaches a maximum of 0.3-0.4 K for a carrier concentration of about 1ϫ10 20 cm Ϫ3 . In spite of its low T c , doped STO, being a very low carrier concentration superconductor, seems to be an ideal model system to exploit the potential demonstrated in recent conventional field effect experiments 2,9,10 and ferroelectric field effect experiments.…”

Electrical properties of La-doped strontium titanate thin films

“…[3][4][5][6] Single-crystal STO has proven to be an excellent substrate for growth of epitaxial metal-oxide films, especially the high temperature superconductors. This and the possibility of controlled doping makes STO a natural material to consider for use in metal-oxide superconductor/semiconductor device applications.…”

Epitaxial growth and transport properties of Nb-doped SrTiO 3 thin films

“…Finally, Fig. 4 shows the T c vs carrier density n for oxygen reduced and Nb doped single crystals adapted from references [2,3]. Using the measured T c value and the carrier density extracted using the high temperature Hall effect measurements, one can position our thin film on this graph.…”