Crystal and electronic structures of -(BEDT-TTF) I under uniaxial strains

Abstract
In order to investigate relationships between the crystal structure and electronic properties, crystal structure analyses of -(BEDT-TTF) ₂I ₃ were performed under in-plane uniaxial strains. It is known that, at ambient pressure, this salt has a semimetallic electronic structure having hole and electronic pockets, and undergoes a metal-insulator transition at 135 K due to a charge disproportionation on BEDT-TTF molecules. Present structure analyses showed that the sizes of both hole and electron like pockets on the Fermi surface rather decreased under a-axial strain, while those of hole ones increased under b-axial strain. These results are qualitatively consistent with observed behaviors of the metal-insulator transition under uniaxial strains. Key words. Organic conductor; Uniaxial strain; Crystal structure analysis.