Interplay between charge and spin correlations and superconducting collective modes in the double-layer high-Tc cuprate HgBa2CaCu2O6+x

Our recent resonant inelastic X-ray scattering (RIXS) study revealed that HgBa2CaCu2O6+x (Hg1212) possesses a relatively high energy scale of paramagnon excitations besides to its high Tc. The paramagnon spectra at low temperature exhibit pronounced anomalies near the wave vector of charge-density- wave (CDW) correlations, hence suggesting an intriguing interplay between the spin and charge degrees of freedom. Moreover, our preliminary sigma-polarization data show an excitation below Tc, which might be an indication of the long-predicted collective charge excitations associated with the superconducting condensate. Hereby we propose to perform a RIXS experiment on Hg1212, in order to study the temperature evolution of the paramagnon anomaly near the CDW wave vector, and to verify the existence of the collective modes related to the superconductivity.