Dependence of the Superconducting Transition Temperature on Carrier Concentration in Semiconducting SrTiO3

1965 ◽  
Vol 14 (9) ◽  
pp. 305-307 ◽  
Author(s):  
J. F. Schooley ◽  
W. R. Hosler ◽  
E. Ambler ◽  
J. H. Becker ◽  
Marvin L. Cohen ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Carrier Concentration ◽  
Superconducting Transition Temperature ◽  
Superconducting Transition

scholarly journals Unconventional Co-Existence of Insulating Nano-Regions and Conducting Filaments in Reduced SrTiO3: Mode Softening, Local Piezoelectricity, and Metallicity

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 437
Author(s):  
Annette Bussmann-Holder ◽  
Hugo Keller ◽  
Arndt Simon ◽  
Gustav Bihlmayer ◽  
Krystian Roleder ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Carrier Concentration ◽  
Superconducting Transition Temperature ◽  
Superconducting Transition ◽  
First Principles Calculations ◽  
Effective Electron ◽  
Mode Softening ◽  
Component Type ◽  
Electron Phonon Coupling ◽  
Transverse Optic

Doped SrTiO3 becomes a metal at extremely low doping concentrations n and is even superconducting at n < 1020 cm−3, with the superconducting transition temperature adopting a dome-like shape with increasing carrier concentration. In this paper it is shown within the polarizability model and from first principles calculations that up to a well-defined carrier concentration nc transverse optic mode softening takes place together with polar nano-domain formation, which provides evidence of inhomogeneity and a two-component type behavior with metallicity coexisting with polarity. Beyond this region, a conventional metal is formed where superconductivity as well as mode softening is absent. For n ≤ nc the effective electron-phonon coupling follows the superconducting transition temperature. Effusion measurements, as well as macroscopic and nanoscopic conductivity measurements, indicate that the distribution of oxygen vacancies is local and inhomogeneous, from which it is concluded that metallicity stems from filaments which are embedded in a polar matrix as long as n ≤ nc.

CHARACTERISTICS OF Y1-xCaxBa2Cu3O7-δ THIN FILMS GROWN BY DC MAGNETRON SPUTTERING

2005 ◽  
Vol 19 (12) ◽  
pp. 581-584
Author(s):  
Z. WANG ◽  
Y. Z. ZHANG ◽  
X. F. LU ◽  
H. GAO ◽  
S. L. JIA ◽  
...  
Keyword(s):  
Thin Films ◽  
Transition Temperature ◽  
Magnetron Sputtering ◽  
Carrier Concentration ◽  
Superconducting Transition Temperature ◽  
Oxygen Atmosphere ◽  
Deposition Condition ◽  
Superconducting Transition ◽  
Dc Magnetron Sputtering ◽  
Annealing Pressure

Epitaxial Y 1-x Ca x Ba 2 Cu 3 O 7-δ thin films were successfully prepared by dc magnetron sputtering. The optimal deposition condition was determined. We find that the superconducting transition temperature Tc of thin films can be easily adjusted by annealing them in oxygen atmosphere with different pressures. Parabola curves are found for both Tc versus carrier concentration and Tc versus annealing pressure relations.

scholarly journals Enhancing Superconductivity of the Nonmagnetic Quasiskutterudites by Atomic Disorder

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5830
Author(s):  
Andrzej Ślebarski ◽  
Maciej M. Maśka
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
High Temperature Superconductors ◽  
Superconducting Phase ◽  
Length Scale ◽  
Superconducting Transition ◽  
Atomic Disorder ◽  
Strong Inhomogeneity ◽  
Related Compounds

We investigated the effect of enhancement of superconducting transition temperature Tc by nonmagnetic atom disorder in the series of filled skutterudite-related compounds (La3M4Sn13, Ca3Rh4Sn13, Y5Rh6Sn18, Lu5Rh6Sn18; M= Co, Ru, Rh), where the atomic disorder is generated by various defects or doping. We have shown that the disorder on the coherence length scale ξ in these nonmagnetic quasiskutterudite superconductors additionally generates a non-homogeneous, high-temperature superconducting phase with Tc⋆>Tc (dilute disorder scenario), while the strong fluctuations of stoichiometry due to increasing doping can rapidly increase the superconducting transition temperature of the sample even to the value of Tc⋆∼2Tc (dense disorder leading to strong inhomogeneity). This phenomenon seems to be characteristic of high-temperature superconductors and superconducting heavy fermions, and recently have received renewed attention. We experimentally documented the stronger lattice stiffening of the inhomogeneous superconducting phase Tc⋆ in respect to the bulk Tc one and proposed a model that explains the Tc⋆>Tc behavior in the series of nonmagnetic skutterudite-related compounds.

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