Phonon mechanism in the most dilute superconductor n-type SrTiO3
Abstract
Low-temperature superconductivity of SrTiO3 gives insight into high-TC (up to 110 K) superconductivity in atomic-thin FeSe layers on SrTiO3. In low-doped SrTiO3 long-range electron interactions with longitudinal (LO) polar modes provide the unique pairing mechanism. Frequencies of polar modes larger than the Fermi energy imply nonadiabatic pairing rather than the usual separate treatment of electron and phonon degrees of freedom. Transport experiments reveal the mobility edge. Random localized states control the interaction between electrons and LO phonons via the magnitude of the dielectric constant. TC is proportional to the Fermi energy. Interaction of the FeSe electrons with surface LO phonons is governed by the dielectric constant at a diffuse surface. Larger 2D Fermi surface results in higher TC for FeSe/SrTiO3.
- Publication:
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Proceedings of the National Academy of Science
- Pub Date:
- April 2016
- DOI:
- 10.1073/pnas.1604145113
- arXiv:
- arXiv:1508.00529
- Bibcode:
- 2016PNAS..113.4646G
- Keywords:
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- Condensed Matter - Superconductivity;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- 5 figures