We explain the phase diagram of the metal-insulator transition observed in a family of organic salts called DCNQI-Cu, assuming phenomenological free energies for the metallic and insulating phases. We point out that the heavy-electron mass is essential for the observed occurrence of the metal-insula
Theory of metal insulator transition of DCNQI-Cu
โ Scribed by Masaru Kato; Masahiro Nakano; Kosaku Yamada
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 142 KB
- Volume
- 194-196
- Category
- Article
- ISSN
- 0921-4526
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โฆ Synopsis
We investigate the metal insulator transition of quasi-one dimensional organic conductors (DCNQI)2Cu by slave boson method. Within mean field approximation, we find that three interactions are needed for these organic conductors getting into insulator phase. These are an on-site Coulomb repulsion on Cu ions, an interaction between conduction electrons and phonons, and Jatm-Tdler effect of d-electrons of Cu ions. Also we find that temperature dependence of the free energies of metal state and insulator state agrees with the assumption of our phenomenological theory.
๐ SIMILAR VOLUMES
Electrical resistivity of (MeBr-DCNQI)2CuI\_xLi x shows that the metal-insulator transition of (MeBr-DCNQI)2Cu at 155 K is rapidly suppressed with increasing x. The mixed-cation system with x=0.2-0.5 retains a metallic state down to 4 K. The metal instability of DCNQI-Cu is discussed in the light of
Two mean-field models describing the metal-insulator phase transition are studied. In the model due to Keldysh and Kopaev (1964) different effective masses in the valence and conduction bands are considered and in the model due to Mattis and Langer (1970) the exact S.C. and b.c.c. densities of state