CM - AMO SEMINAR | Searching for the Genes of Unconventional High Temperature Superconductors

In the past, both curates and iron-based superconductors were discovered accidentally. Lacking of successful predictions on new high Tc materials is one of major obstacles to reach a consensus on the high Tc mechanism. In this talk, we discuss two emergent principles, which are called as the correspondence principle  and the selective magnetic pairing rule, to unify the understanding of both cuprates and iron-based superconductors. These two principles  provide an unified explanation why the d-wave pairing symmetry and the s-wave pairing symmetry are robust respectively in cuprates and iron-based superconductors. In the meanwhile, the above two principles explain the rareness of unconventional high Tc superconductivity, identify necessary electronic environments  required for high Tc superconductivity and  finally serve as  direct guiding rules to search   new   high Tc materials. We predict that the third family of unconventional  high  Tc superconductors exist in the compounds which carry   two dimensional hexagonal lattices formed by cation-anion trigonal bipyramidal complexes with a d7 filling configuration  on the cation ions. Their superconducting states are expected to  be dominated by  the  d+id  pairing symmetry and their maximum Tc should be higher than those of iron-based superconductors. Verifying the prediction can convincingly establish the high Tc superconducting mechanism and pave a way to design new high Tc superconductors.