Prominent electron-phonon coupling in high-Tc cuprates under apical orbital-selective excitation

Author: Li, Yuan

Affiliation: Institute of Physics, Chinese Academy of Sciences

Type: Contributed Talk

Session: Cuprates II

Date and Time: 20.07.2026, 18:00 - 18:20

The role of electron-phonon interactions in cuprates remains contested, and most studies thus far have focused on the CuO2 sheets. Here we use oxygen-K-edge resonant inelastic X-ray scattering (RIXS) to probe apical oxygen-derived electron-phono coupling, by studying the trilayer model cuprate HgBa2Ca2Cu3O8+x (Hg1223) alongside other cuprates. When both incident photon energy and polarization are tuned to the apical-oxygen 1s-to-2pz transition, the RIXS spectra exhibit a prominent ladder of phonon overtones, evenly spaced by 70 meV, whose intensities follow a Franck-Condon envelope, signaling exceptionally strong coupling of oxygen c-axis vibrations to the excited electronic states. The significance of this strong coupling will be discussed, such as its ability to cause a dispersion kink of the quasiparticles.