Superconductivity at very low density: The case of strontium titanate
Name
PhysRevB.94.224515.pdf
Size
1.18 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Ruhman, Yehonatan
Lee, Patrick A
Date Issued
December 2016
Journal
Physical Review B
Publisher
American Physical Society
Citation
Ruhman, Jonathan, and Patrick A. Lee. “Superconductivity at Very Low Density: The Case of Strontium Titanate.” Physical Review B 94.22 (2016): n. pag.
Version
Final published version
Abstract
Doped strontium titanate becomes superconducting at a density as low as n = 5 x 10[superscript 17] cm[superscript -3], where the Fermi energy is orders of magnitude smaller than the longitudinal-optical-phonon frequencies. In this limit, the only optical mode with a frequency which is smaller than the Fermi energy is the plasmon. In contrast to metals, the interaction strength is weak due to screening by the crystal, which allows the construction of a controllable theory of plasmon superconductivity. We show that plasma mediated pairing alone can account for the observed transition temperatures only if the dielectric screening by the crystal is reduced in the slightly doped samples compared with the insulating ones. We also discuss unique features of the plasmon mechanism, which appear in the tunneling density of states above the gap.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1103/PhysRevB.94.224515
