Signatures of mesoscopic Jahn–Teller polaron inhomogeneities in high-temperaturesuperconductors

Abstract

We analyse complementary experimental results in high-temperature superconductingcuprates from x-ray absorption fine structure (XAFS), inelastic neutron scattering(INS) and inelastic x-ray scattering (IXS), Raman spectroscopy (RS), infraredabsorption spectroscopy and femtosecond optical spectroscopy in terms of thepredictions of a specific fully quantum mechanical calculation of small polaronformation and internal dynamics (phonon-assisted local charge oscillations). Theseanalyses support the scenario in which the pseudogap-associated temperature,T*,marks the onset of an inhomogeneous ground state with polarons, in agreementwith several theoretical models which attempt to explain the origin ofhigh-temperature superconductivity in doped cuprates. The change in dynamics,which is observed across the superconducting transition temperature,Tcin XAFS, INS and RS, indicates an intimate link of the dynamics of thesepolarons with the mechanism of high-temperature superconductivity.