Superconductivity in cuprates governed by topological constraints

Abstract

The remarkable universality of the cuprate $T_c$ dome suggests a very fundamental unifying principle. Moreover, the superconducting gap is known to persist above $T_c$ in the pseudogap phase of all cuprates. So, contrary to BCS, the gap cannot be the order parameter of the transition. In this work, we show that both the $T_c$-dome and the pseudogap line $T^*(p)$ arise from a unique and identifiable principle: the interaction of localized `pairons' on an antiferromagnetic square lattice. The topological constraints on such preformed pairons give rise to both the $T_c$ dome and the pairing energy {\it simultaneously}. It also provides a natural explanation for the critical doping points of the phase diagram. The model matches perfectly both the $T^*$ and $T_c$ experimental lines, with only one adjustable parameter.