Understanding the totally symmetric intramolecular vibrations in κ-phase organic superconductors -: art. no. 214514

We report magnetoinfrared measurements of two quasi-isostructural kappa-phase organic molecular solids: kappa-(ET)(2)Cu[N(CN)(2)]Br (T-c=11.6 K) and the nonsuperconducting kappa-(ET)(2)Cu[N(CN)(2)]Cl analog. Our results support the contributing role of electron-molecular vibrational coupling to superconductivity in layered organic superconductors, and we identify the most important totally symmetric modes in kappa-(ET)(2)Cu[N(CN)(2)]Br within the nonplanar molecular building block picture.