Mott Insulator to high \tc Superconductor via Pressure: Resonating Valence Bond theory and prediction of new Systems

Abstract

Mott insulator superconductor transition, via pressure and no external doping, is studied in orbitally non degenerate spin-\half systems. It is presented as another RVB route to high \tc superconductivity. We propose a `strong coupling' hypothesis which helps to view first order Mott transition as a self doping process that also preserves superexchange on metal side . We present a generalized t-J model where a conserved $N_0$ doubly occupied ($e^-$) sites and $N_0$ empty sites ($e^+$) hop in the background of $N - 2 N_0$ singly singly occupied (neutral) sites in a lattice of N sites. An equivalence to the regular t-J model is made and some old and new systems are predicted to be candidates for pressure induced high \tc superconductivity.