Electrostatic modulation of the electronic properties of Nb-doped SrTiO[sub 3] superconducting films.

We have performed ferroelectric field effect experiments using an epitaxial heterostructure composed of ferroelectric Pb(Zr[sub 0.2]Ti[sub 0.8])O[sub 3] and superconducting Nb-doped SrTiO[sub 3]. The films were prepared on (001) SrTiO[sub 3] substrates by off-axis radio-frequency magnetron sputtering and pulsed-laser deposition. By switching the polarization field of the 500-Å-thick Pb(Zr[sub 0.2]Ti[sub 0.8])O[sub 3] layer, a large change of about 30% in resistivity and a 20% shift of T[sub c] (ΔT[sub c]∼0.05 K) were induced in the 400-Å-thick epitaxial Nb-doped SrTiO[sub 3] layer. The relationship between T[sub c] and the electrostatically modulated average carrier concentration can be mapped onto the phase diagram of chemically doped SrTiO[sub 3]. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]