A new study published in Physical Review Letters (PRL) explores the potential of quadratic electron-phonon coupling to enhance superconductivity through the formation of quantum bipolarons.
Electron-phonon coupling is the interaction between electrons and vibrations in a lattice called phonons. This interaction is crucial for superconductivity (resistance-free electrical conductance) in certain materials as it facilitates the formation of Cooper pairs.
Cooper pairs are pairs of electrons bound together via attractive interactions. When these Cooper pairs condense into a coherent state, we get superconducting properties.
Electron-phonon coupling can be categorized based on its dependence on phonon displacement, which means how much the lattice vibrates. The most commonly considered case is when electron density linearly couples to lattice displacements, causing a lattice distortion to surround every electron.
The researchers wanted to study if superconductivity can be enhanced for materials exhibiting quadratic coupling, which is when the interaction energy is proportional to the square of the phonon displacement.
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