Superconductivity in Cuprates

Abstract

An insulator with a magnetic moment at each lattice site (i.e. a magnetic insulator) is known as Mott insulator. The unusuality of a Mott insulator is that strong correlations suppress the charge fluctuations, which are required for a finite conductivity. However, doping produces holes in copper–oxygen planes and it becomes susceptible to charge density wave (CDW): charge on a site changes, as the excitation moves, i.e. there is a gap for charge excitations, but no gap for spin excitations. Further, due to doping, long range antiferromagnetic order is replaced by short range order, and superconductivity emerges as the ground state.