Related Experiment Video
Updated: Jul 8, 2025
11:07
Synthesis of Non-uniformly Pr-doped SrTiO3 Ceramics and Their Thermoelectric Properties
Published on: August 15, 2015
9.9K
First-principles calculation of electron-phonon coupling in doped KTaO3.
Tobias Esswein1, Nicola A Spaldin1
1Department of Materials, ETH Zurich, Zürich, Zurich, 8093, Switzerland.
Open Research Europe
|December 20, 2023
Summary
We calculated electron-phonon coupling in KTaO3, finding it strongest in optical modes. This suggests ferroelectric fluctuations, not BCS theory, drive superconductivity in this material.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Materials
Background:
- Superconductivity in KTaO3 single crystals exhibits strong surface-plane dependence.
- Experimental findings motivate theoretical investigation into the underlying mechanisms.
Purpose of the Study:
- To calculate the electron-phonon coupling strength (λ) in doped KTaO3.
- To analyze the mode-resolved distribution of λ along high-symmetry directions in reciprocal space.
Main Methods:
- Utilized the Wannier-function approach within the EPW package.
- Calculated λ across the experimental doping range.
- Compared mode-resolved λ distribution along [001], [110], and [111] directions.
Main Results:
- Electron-phonon coupling (λ) is strongest in optical modes near the Γ point, particularly along the [001] direction.
- The doping dependence of λ exhibits a dome-like shape in all directions.
- Integrated λ is largest along [001] and smallest along [111], contrasting experimental critical temperature trends.
Conclusions:
- The discrepancy with experimental trends suggests a non-BCS mechanism for superconductivity.
- Strong localization of λ in soft optical modes points to the importance of ferroelectric soft-mode fluctuations.
- Mode-resolved λ values are enhanced in polar structures, supporting the role of ferroelectricity.
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