Electronic band structure and point-contact spectroscopy of the organic superconductor β-(BEDT-TTF)2I3

The authors carried out an ab-initio self-consistent electronic band structure calculation for (ET), using the ASW method. In the present case, there are 55 atoms in a unit cell with P anti 1 symmetry i.e. 28 atoms are inequivalent. In addition, 32 empty spheres were used to fill-up the space between the atoms (60% of the total volume). The question of which phonons play the most important role in superconductivity can be investigated experimentally using the techniques of tunneling and point-contact spectroscopy to determine the Eliashberg function α2(omega)F(omega). The authors used point-contact spectroscopy to determine the Eliashberg function, as well as tunneling to determine the superconducting gap