Pressure-Induced One-Dimensional Instability in (DMDCNQI)2Cu

The electrical resistivity of an organic metal, (DMDCNQI) 2 Cu (DMDCNQI: 2, 5-dimethyl-N, N'-dicyanoquinonediimine) is measured under pressure. Though this compound retains a metallic state down to 1.5 K at ambient pressure, a metal semiconductor transition appears above 4.5 kbar, and the transition temperature increases with an increase in pressure. On the analogy of the related compounds, this transition is attributed to a kind of one-dimensional instability.