Local dynamical lattice instabilities: Prerequisites for resonant pairing superconductivity - Condensed Matter > SuperconductivityReport as inadecuate




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Abstract: Fluctuating local diamagnetic pairs of electrons, embedded in a Fermi sea,are candidates for non-phonon-mediated superconductors without the stringentconditions on Tc which arise in phonon-mediated BCS classical low-Tcsuperconductors. The local accumulations of charge, from which such diamagneticfluctuations originate, are irrevocably coupled to local dynamical latticeinstabilities and form composite charge-lattice excitations of the system. Fora superconducting phase to be realized, such excitations must be itinerantspatially phase-coherent modes. This can be achieved by resonant pair tunnelingin and out of polaronic cation-ligand sites. Materials in whichsuperconductivity driven by such local lattice instability can be expected,have a Tc which is controlled by the phase stiffness rather than the amplitudeof the diamagnetic pair fluctuations. Above Tc, a pseudogap phase will bemaintained up to a T*, where this pairing amplitude disappears. We discuss thecharacteristic local charge and lattice properties which characterize thispseudogap phase and which form the prerequisites for establishing aphase-coherent macroscopic superconducting state.



Author: Julius Ranninger, Alfonso Romano

Source: https://arxiv.org/







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