Magnetic pairing of charge carriers in doped Mott insulators

Abstract

The recent discovery of superconductivity in certain CuO{sub 2}-based layered perovskites with transition temperatures (T{sub c} {approximately} 30-125 K) spanning the boiling point of liquid nitrogen (77 K) has been one of the greatest surprises of the physics and chemistry of the transition metal oxides. There are now compelling reasons to believe that the possibly unconventional (non-BCS) superconductivity, the high transition temperatures, and almost certainly the highly anomalous normal-state properties of these layered oxides derive essentially from the strong electron-electron repulsion (correlation) and the low dimensionality found in these systems. In fact, these systems are best viewed as doped Mott insulators in the proximity of the (antiferromagnetic) insulator to (paramagnetic) metal transition. Presented here is a very specific (magnetic) mechanism for singlet pairing of charge carriers doped into the Mott insulators. The mechanism involves an intrinsically strong interaction of the charge carriers with the spin configurations of the antiferromagnetically (AF) correlated background.