Momoka Higa

Electrical and Structural Properties of θ-type BEDT-TTF Organic Conductors under Uniaxial Strain

In order to investigate the relationships between crystal structures and electronic properties of θ-type BEDT-TTF organic conductors, electrical properties of θ-(BEDT-TTF) 2 Ag(CN) 2 and θ-(BEDT-TTF) 2 CsZn(SCN) 4 and crystal structures of θ-(BEDT-TTF) 2 CsZn(SCN) 4 under uniaxial strain are investigated. The resistivity measurements for both salts under uniaxial strain show that the inter-columnar uniaxial strain preserves the metallic nature while the intra-columnar one induces an insulating behavior, which are reminiscent of the charge-ordered state of θ-(BEDT-TTF) 2 RbZn(SCN) 4 . Structure analyses of θ-(BEDT-TTF) 2 CsZn(SCN) 4 under uniaxial strain indicate that the inter-columnar strain slightly increases the diagonal transfer integral but does not vary the vertical one, and the intra-columnar uniaxial strain largely increases the vertical transfer integral but does not change the diagonal one. Based on these experimental results, the key parameters to determine the electrical properties of θ-type B...

A possible internal deformation of the charge ordering and its meta-stability in the organic conductor θ-(BEDT -TTF )2CsZn (SCN )4

Non-ohmic transport was studied by pulse method in the charge-ordered state of the organic conductor θ-(BEDT-TTF) 2 CsZn(SCN) 4 as controlling the electronic state by uniaxial strain method. It was discovered that the non-ohmic conduction under high electric fields lead to the meta-stable state with a structural modification, where the ohmic resistance was reduced to be smaller than the original. The response of the CO state to pulsed electric fields suggested a possible internal deformation of the ordered charges lattice.