Non-fermi liquid correction to uniform spin susceptibility of singlet band below Tc

Abstract

A new expression for the uniform static spin susceptibility below Tc in singlet band model has been deduced. The formula takes into account strong electron correlation effects. The comparison of the theoretical curve with experimental data yields another value of 2Δ/kBTc than in the case of the usual Fermi liquid. In particular, for YBa2Cu3O7 the extracted ratio 2Δ/kBTc = 4.87 and can be interpreted in favor of the superexchange pairing mechanism. © 1998 Elsevier Science Ltd.