Control of electronic properties of organic conductors by uniaxial strain method

Abstract

We succeeded to artificially control the electronic properties of some BEDT-TTF and TMTSF salts by shortening the intermolecular distance along a desired direction without changing those along others (uniaxial strain method). We were able to make α-(BEDT-TTF) 2 KHg(SCN) 4 and its NH 4 analogue behave similarly to each other by controlling the lattice parameters a and c independently. The former compound was found to show the superconductivity like the latter and the latter the nesting instability like the former. It is possible to systematically understand the electronic properties of these materials as a function of c/a. In (TMTSF) 2 PF 6 , contrary to conventional expectations, the reduction of the lattice parameter a, but not those perpendicular to a, plays a key role to suppress the SDW and induces the superconductivity.