Structural and electronic properties of α, β-(BEDT-TTF)₂I₃ and κ-(BEDT-TTF)₂X₃ (X=I,F,Br,Cl) organic charge transfer salts

Studies of organic crystalline materials have become an active area of research over the past few decades. Physical properties of some of these materials can be tuned with relative ease utilizing minor modifications of their structures by applying pressure or chemical substitution. One class of such compounds is the BEDT-TTF-based charge transfer salts that are packed in a quasi-two-dimensional structure. Using first principles calculations, we have studied α, β and κ-phases of (BEDT-TTF)₂I₃ as well as chemical substitutions of other Halogens in the κ-phase, which has a non-symmorphic space group (1). The κ-phase, under the anion substitution I-> F, shows a topological transformation in its band structure near the Fermi level. In addition, we are evaluating the superconducting order parameter and its symmetry properties of some of these phases through a Bethe-Salpeter approach.

(1) Commeau, et al. PRB 96.12 (2017): 125135.