Selectively deuterated molecular conducfor (DMe-DCNQI)/sub 2/-phase diagram and dimensionality

Summary form only given. Conducting molecular system (R/sup 1/,R/sup 2/-DCNQI)/sub 2/Cu consists of one dimensional DCNQI columns, each of which is three-dimensionally linked by the coordination bond (Cu-N). P//sup/spl pi-d// interaction in this system provides unique electrical and magnetic properties. (DMe-DCNQI)/sub 2/Cu undergoes novel metal-insulator-metal (reentrant) transition under very low-pressure. Based on the discovery of the deuteration-induced metal-insulator transition/sup 1/), we present fine tuning of the effective pressure (1-500 bar) by selective deuteration of the DMe-DCNQI molecule. Structural and electrical aspects of the phase transition in the selectively deuterated system (including alloy system) are described. We also report that three-dimensional Fermi surface observed in the de-Haas van Alphen effect/sup2/) can be explained by a simple tight-binding band calculation.