First-principles theoretical study of metallic states of DCNQI-(Cu,Ag,Li) systems

The detailed electronic structures of several materials of organic solids, (${\mathit{R}}_1$,${\mathit{R}}_2$-DCNQI${)}_2$M, were studied with the first-principles method based on the local-density approximation supplemented by the generalized gradient approximation. The present calculations account well for the qualitative differences in the electronic properties produced by different metal cations (M=Li, Ag, and Cu). Unique aspects of the systems with ${\mathit{R}}_1$=${\mathit{R}}_2$=I are also explained based on the present calculations. The very small hole Fermi surface observed by the de Haas–van Alphen measurement for (DMe-DCNQI${)}_2$Cu was well reproduced by the calculation with the observed crystal structure. © 1996 The American Physical Society.