Abstract: Although there is no complete theory of high temperature superconductivity, the importance of CuO2 planes in cuprate superconductors is confirmed from both theory and experiments. Strong Coulomb repulsion between electrons on the CuO2 plane makes the resultant electron system highly correlated and a difficult problem to solve since exact solutions of the many-body Hamiltonian in two dimensions do not exist. If however, superconductivity can arise in structures having chains rather than planes and having a high critical temperature, then the high temperature superconductivity problem could become more tractable since exact solutions in one dimension do exist. In this talk, I will describe the observation of bulk superconductivity in single crystals of a cuprate SrxCa1-xCuO2 at very high critical temperature, Tc, of ~ 90 K whose structure reveals the presence of infinite double chains of Cu-O-Cu-O instead of CuO2 planes, thus, ensuring quasi-one dimensional superconductivity. Bulk superconducting behaviour was observed in dc magnetisation, ac susceptibility as well as resistance measurements. The observation of bulk superconductivity in SrxCa1-xCuO2 having chains of Cu-O-Cu-O rather than planes of CuO2 at a high Tc of 90 K is expected to profoundly impact our understanding of high temperature superconductivity.

Tea: 10:50am