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Predictive calculation of high temperature superconductors

Accurate calculation of transition temperature

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Graduate School of Engineering / Faculty of Engineering
2013/08/29

Prediction or materials design of high temperature superconductivity is one of the holy grails of condensed matter theory. To achieve this goal, researchers need to develop a predictive method to calculate transition temperatures of superconductors mediated by phonons, plasmons, excitons, spin fluctuations, and so on. While density functional theory for phonon-mediated superconductors was successfully formulated in 2005, it has proved difficult to develop for unconventional superconductors that often have extremely high transition temperatures. Professor Ryotaro Arita and Mr. Ryosuke Akashi from the Department of Applied Physics, the University of Tokyo, formulated a scheme for the plasmon mechanism, a prototypical unconventional pairing mechanism whose history dates back to late 1970s. They applied their method to one of the most elemental high temperature superconductors, lithium under pressure, and obtained excellent agreement between theory and experimental data.

© Ryotaro Arita, Comparison of predicted superconducting transition temperatures using the previous method (red) and the new method (violet), plotted together with the experimentally observed values reported by four groups (open circle, triangle, square, and diamond). The previous method which takes into account only the lattice vibration results in underestimation, whereas the new method gives more accurate prediction by considering the electronic vibration.

This method provides an index against which to design new superconducting materials that should accelerate the development of new synthetic superconductors and contribute to the future creation of superconducting power lines and motors.

This research was published in the journal Physical Review Letters (August 1 online edition).

Press release

Paper

Ryosuke Akashi and Ryotaro Arita,
“Development of Density-Functional Theory for a Plasmon-Assisted Superconducting State: Application to Lithium Under High Pressures”,
Physical Review Letters 111, 057006 (2013), doi: 10.1103/PhysRevLett.111.057006.
Article link

Links

Graduate School of Engineering

Department of Applied Physics, Graduate School of Engineering

Arita Laboratory, Department of Applied Physics, Graduate School of Engineering

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