Crystal growth and doping control of HgBa2CuO4+δ, the model compound for high-T superconductors

International audienceA self-flux method to grow very high quality single crystals of the superconducting HgBa2CuO4+δ mercury cuprates is reported. The single crystals are platelet-shaped, with surfaces of high optical quality and good crystallographic properties. Annealing enables optimization of Tc up to Tc max = 94 K. With adequate treatment, the doping level of the crystalline samples can be finely controlled in a wide under-and over-doped range. Preliminary structural characterization from single crystal X-ray diffraction data is given for different doping levels. The signature of under-and over-doping for both pure and gold-substituted crystals has been identified from micro-Raman spectroscopy measurements