In order to control the electronic states of organic conductors, two methods, (a) band filling and (b) bandwidth controls, have been applied. As for (a), it is the first time in organic conductors that the band filling in α-ET3(GaCl4)-11-x (CoCl4)-2x(TCE) (x = 0.38, 0.43, 0.46, 0.64, 1.00) is controlled systematically. For (b), the bandwidth control has been carried out by chemical and physical methods in λ-D2GaCl4 (D = ET, us-STF, BETS). By applying pressure, the system transfers from an antiferromagnetic insulator (λ-ET2GaCl4), a metallic state down to 1.3 K (λ-(us-STF)2GaCl4 under 18 kbar), to a superconductor (λ-BETS2GaCl4). It is clarified that the λ-type organic superconductor has been obtained by the bandwidth control of the antiferromagnetic insulator.
- Organic conductors based upon cation and/or anion radical salts
- Transport measurements