Inhaltszusammenfassung

SrTiO3−δ can show metallic behavior and superconductivity at T<500 mK. Due to its low carrier concentration (1020 cm−1) and huge dielectric polarisability (ε300) this compound is considered as a candidate for a polaronic superconducting pairing mechanism. It is demonstrated that by variation of the annealing temperature in vacuum the transport properties of SrTiO3−δ can be tuned continuously from semiconducting to metallic. We present measurements of the upper critical field Bc2(T) which s...SrTiO3−δ can show metallic behavior and superconductivity at T<500 mK. Due to its low carrier concentration (1020 cm−1) and huge dielectric polarisability (ε300) this compound is considered as a candidate for a polaronic superconducting pairing mechanism. It is demonstrated that by variation of the annealing temperature in vacuum the transport properties of SrTiO3−δ can be tuned continuously from semiconducting to metallic. We present measurements of the upper critical field Bc2(T) which show near Tc a positive curvature. This unusual temperature dependence is consistent with a model of weakly interacting charged bosons which condense in the superconducting state (local pairing). However, measurements of current–voltage curves reveal only small critical currents of our samples. This observation is discussed in the framework of doping inhomogeneities. » weiterlesen» einklappen

Autoren

Klassifikation

DFG Fachgebiet:
Physik der kondensierten Materie

DDC Sachgruppe:
Physik