New BEDT-TTF Radical Cation Salt with Mixed Anions: α'-[BEDT-TTF]2[CuBr2]0.4[CuCl2]0.6

A new mixed-anion crystal composed of BEDT-TTF radical cation salt [BEDT-TTF] 2(CuBr 2) 0.4(CuCl 2) 0.6 with an α'-type donor arrangement with a formal charge of +0.5 per BEDT-TTF was prepared by using a chemical oxidation method and characterized by using X-ray diffraction, four-probe electrical resistivity measurements (semiconductor: ρ rt = 2 × 10 2 Ω cm, E a = 0.2 eV), and energy band calculations. The results showed that this system had a quasi-one dimensional Fermi surface.