Comment on “Superconductivity at low density near a ferroelectric quantum critical point: Doped SrTiO3”
Abstract
Wölfle and Balatsky have proposed a microscopic pairing mechanism for doped SrTiO3 (STO) based on the gradient coupling of electronic density to the soft transverse optical (TO) phonon mode. Since this coupling to TO phonons is usually weak, this conclusion is surprising, especially for a low-density superconductor such as STO, where the density of states is small. A crucial step in the argument made by Wölfle and Balatsky is that the displacement vector of the TO mode is not strictly perpendicular to the momentum vector, making a deformation coupling possible. We show that they have made a mistake in computing the eigenvector and have grossly overestimated this lack of orthogonality. When corrected, the coupling is negligible. We also use transport data to put upper bounds on the coupling constant which are much smaller than the estimate by Wölfle and Balatsky. Lastly, we also object to their use of the Eliashberg equation when the phonon frequency is larger than the Fermi energy.
- Authors:
-
- Bar Ilan Univ., Ramat Gan (Israel)
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- Publication Date:
- Research Org.:
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); Israeli Science Foundation
- OSTI Identifier:
- 1777856
- Grant/Contract Number:
- FG02-03ER46076; 967/19
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Physical Review B
- Additional Journal Information:
- Journal Volume: 100; Journal Issue: 22; Journal ID: ISSN 2469-9950
- Publisher:
- American Physical Society (APS)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Electron-phonon coupling; Methods in superconductivity; Superconductors
Citation Formats
Ruhman, Jonathan, and Lee, Patrick A. Comment on “Superconductivity at low density near a ferroelectric quantum critical point: Doped SrTiO3”. United States: N. p., 2019.
Web. doi:10.1103/physrevb.100.226501.
Ruhman, Jonathan, & Lee, Patrick A. Comment on “Superconductivity at low density near a ferroelectric quantum critical point: Doped SrTiO3”. United States. https://doi.org/10.1103/physrevb.100.226501
Ruhman, Jonathan, and Lee, Patrick A. Fri .
"Comment on “Superconductivity at low density near a ferroelectric quantum critical point: Doped SrTiO3”". United States. https://doi.org/10.1103/physrevb.100.226501. https://www.osti.gov/servlets/purl/1777856.
@article{osti_1777856,
title = {Comment on “Superconductivity at low density near a ferroelectric quantum critical point: Doped SrTiO3”},
author = {Ruhman, Jonathan and Lee, Patrick A.},
abstractNote = {Wölfle and Balatsky have proposed a microscopic pairing mechanism for doped SrTiO3 (STO) based on the gradient coupling of electronic density to the soft transverse optical (TO) phonon mode. Since this coupling to TO phonons is usually weak, this conclusion is surprising, especially for a low-density superconductor such as STO, where the density of states is small. A crucial step in the argument made by Wölfle and Balatsky is that the displacement vector of the TO mode is not strictly perpendicular to the momentum vector, making a deformation coupling possible. We show that they have made a mistake in computing the eigenvector and have grossly overestimated this lack of orthogonality. When corrected, the coupling is negligible. We also use transport data to put upper bounds on the coupling constant which are much smaller than the estimate by Wölfle and Balatsky. Lastly, we also object to their use of the Eliashberg equation when the phonon frequency is larger than the Fermi energy.},
doi = {10.1103/physrevb.100.226501},
journal = {Physical Review B},
number = 22,
volume = 100,
place = {United States},
year = {Fri Dec 20 00:00:00 EST 2019},
month = {Fri Dec 20 00:00:00 EST 2019}
}
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Works referenced in this record:
Quantum effects in incipient and low-temperature ferroelectrics (a review)
journal, August 2001
- Kvyatkovskii, O. E.
- Physics of the Solid State, Vol. 43, Issue 8
Intrinsic Mobility Limiting Mechanisms in Lanthanum-Doped Strontium Titanate
journal, May 2014
- Verma, Amit; Kajdos, Adam P.; Cain, Tyler A.
- Physical Review Letters, Vol. 112, Issue 21
Theory of Superconductivity in Polar Semiconductors and Its Application to N-Type Semiconducting SrTiO 3
journal, October 1980
- Takada, Yasutami
- Journal of the Physical Society of Japan, Vol. 49, Issue 4
Ferroelectric quantum criticality
journal, March 2014
- Rowley, S. E.; Spalek, L. J.; Smith, R. P.
- Nature Physics, Vol. 10, Issue 5
Quantum Critical Origin of the Superconducting Dome in
journal, December 2015
- Edge, Jonathan M.; Kedem, Yaron; Aschauer, Ulrich
- Physical Review Letters, Vol. 115, Issue 24
Electron-Phonon Scattering in the Presence of Soft Modes and Electron Mobility in Perovskite from First Principles
journal, November 2018
- Zhou, Jin-Jian; Hellman, Olle; Bernardi, Marco
- Physical Review Letters, Vol. 121, Issue 22
Superconductivity at low density near a ferroelectric quantum critical point: Doped
journal, September 2018
- Wölfle, Peter; Balatsky, Alexander V.
- Physical Review B, Vol. 98, Issue 10
Superconductivity at very low density: The case of strontium titanate
journal, December 2016
- Ruhman, Jonathan; Lee, Patrick A.
- Physical Review B, Vol. 94, Issue 22
Scalable T2 resistivity in a small single-component Fermi surface
journal, August 2015
- Lin, X.; Fauque, B.; Behnia, K.
- Science, Vol. 349, Issue 6251
Theory of the quantum paraelectric-ferroelectric transition
journal, January 2003
- Roussev, R.; Millis, A. J.
- Physical Review B, Vol. 67, Issue 1
Superconductivity from nonphonon interactions
journal, June 1984
- Grabowski, M.; Sham, L. J.
- Physical Review B, Vol. 29, Issue 11