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

摘要

Mott insulator superconductor transition, via pressure and no externaldoping, is studied in orbitally non degenerate spin-\half systems. It ispresented as another RVB route to high \tc superconductivity. We propose a`strong coupling' hypothesis which helps to view first order Mott transition asa self doping process that also preserves superexchange on metal side . Wepresent 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 $N - 2 N_0$ singlysingly occupied (neutral) sites in a lattice of N sites. An equivalence to theregular t-J model is made and some old and new systems are predicted to becandidates for pressure induced high \tc superconductivity.