APRES study of the High temperature cuprates with high superconducting transition temperature (T$_{c}>$90K)

The curprates with high superconducting transition temperature, nearly optimally doped HgBa$_{2}$CuO$_{4+\delta }$ system ( Hg1201, T$_{c}$=96K) and nearly optimally-doped TlBa2Ca$_{2}$Cu$_{3}$ O$_{8+\delta }$ ( Tl1223, T$_{c}$=120K), were studied by the Angle Resolved Photoemission Spectroscopy (ARPES). These materials provide us an opportunity to examine the universal properties of the cuprates and their material dependence trend. Although they are not easy to be cleaved, we managed to measure the band dispersions and the Fermi surfaces of these materials. Interestingly, in Hg1201 system, we found the existence of a quasi-particle peak along (0,0) to ($\pi $,$\pi )$ direction (nodal direction); whereas no structure was observed near the zone boundary. Contrarily, in Tl1223 system, a well-defined peak in EDCs was observed near the zone boundary; whereas no peak was observed in the nodal region. A comparison to other most studied cuprates will also be presented.