Imaging the effect of electron lattice interactions on high-Tc superconductivity in Bi2Sr2CaCu2O8+δ

Abstract

One of key challenges in high-Tc superconductivity research is to identify a predominant mechanism controlling superconductivity at atomic scale. Using the spectroscopic imaging scanning tunnelling microscopy technique[1] we find a ~9±1% sinusoidal variation in local energy gap Δ triggered by the crystal ‘supermodulation’ revealing a strong non-random out-of-plane effect on superconductivity[2], substitutional isotope effect on the d2I/dV2 spectrum reveals 6% reduction of mode energy Ω indicating the involvement of the lattice vibrations that couple strongly to the quasiparticle states of Bi2Sr2CaCu2O8+δ [3]. We also find that the heterogeneous electronic states coupling to the lattice only occur above a certain energy which separates the spatially homogeneous and heterogeneous excitations[4].