Light bipolarons from strong Peierls electron-phonon coupling
Invited
Abstract
It is widely accepted that phonon-mediated high-temperature superconductivity is impossible at ambient pressure, because of the very large effective masses of polarons and bipolarons at strong electron-phonon coupling. We challenge this by showing that strongly bound yet very light bipolarons appear for strong Peierls coupling. These bipolarons exhibit many unconventional properties; e.g., at strong coupling there are two low-energy bipolaron bands that are stable against strong Coulomb repulsion. Using numerical simulations and analytical arguments, we show that these properties result from the specific form of the phonon-mediated interaction, which is of “pair hopping” instead of regular density-density type. This unusual effective interaction is bound to have nontrivial consequences for the superconducting state expected to arise at finite carrier concentrations and should favor a large critical temperature.
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Presenters
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Mona Berciu
University of British Columbia, Physics and Astronomy, University of British Columbia, Stewart Blusson Quantum Matter Institute, University of British Columbia
Authors
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Mona Berciu
University of British Columbia, Physics and Astronomy, University of British Columbia, Stewart Blusson Quantum Matter Institute, University of British Columbia
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John Sous
Physics, Columbia University, Columbia Univ, Columbia University, Departments of Physics and Chemistry, Columbia University
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Monodeep Chakraborty
Centre for Theoretical Physics, Indian Institute of Techology, Kharagpur
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Roman Krems
Chemistry, University of British Columbia