%0 Journal Article
%T Probing the energy gap of high-temperature cuprate superconductors by resonant inelastic x-ray scattering
%J -
%D 2018
%R https://doi.org/10.1038/s41535-018-0139-7
%X The determination of the symmetry of the energy gap is crucial for research on the microscopic mechanisms of unconventional superconductivity. Here, we demonstrate experimentally that high-resolution resonant inelastic X-ray scattering at the Cu L3 edge can serve as a momentum-resolved, bulk-sensitive probe of the superconducting gap. We studied two optimally doped cuprates Bi2Sr2CaCu2O8+¦Ä and Bi2Sr2Ca2Cu3O10+¦Ä, in which we observe a strongly momentum dependent reduction of the spectral weight upon entering the superconducting state, with a maximum for momenta connecting antinodal regions of the Fermi surface. Based on a comparison with the calculated charge susceptibility and electronic Raman scattering data, we interpret our observation as a renormalization of the non-local charge susceptibility due to the superconducting gap opening. Our data demonstrate the methodological potential of resonant inelastic X-ray scattering as a versatile probe of the energy gap of high-temperature superconductors, including buried interfaces in heterostructures which are inaccessible to angle-resolved photoemission spectroscopy
%U https://www.nature.com/articles/s41535-018-0139-7