Nematic response to uniaxial pressure of 2D charge density waves in YBa2Cu3O6.67 investigated by Cu-L3 RIXS

In the framework of the investigations of charge order and high-Tc superconductivity in cuprates, our pioneering x-ray scattering work using uniaxial pressure has shown that 2D charge density waves (CDW) are enhanced in the direction perpendicular to that of applied stress in YBa2Cu3O6+x (YBCO) crystals. Crucially, our results on 2D-CDW can be explained in terms of strong nematic susceptibility which results in a symmetric response to compressive stress applied either to the a- or b-axis and makes alternatively energetically favourable the b- or a-CDW domains, respectively, on top of pre-existing domains pinned by defects. We propose to carry out Cu-L3 resonant inelastic x-ray scattering on YBCO under uniaxial pressure to investigate this scenario. We will compare the a- and b-CDW peaks upon cooling the crystals with and without applied stress and we will map the 2D Brillouin Zone in search of ring-like dynamic charge density fluctuations condensing to static CDW at low temperature.