Point-contact spectroscopy of the organic superconductor <i>β</i>-(BEDT-TTF)2I3

Homo- and heterojunctions (with Cu and Ag) of the organic superconductor β-(BEDT-TTF)) 2I3 in the normal state are investigated. The IVC of point contacts and their second derivatives (point-contact spectra) are measured in the voltage range 0–250 mV. Two types of point contact spectra are observed. The first type includes the curves displaying peculiarities in the entire voltage range under investigation. The second type is characterized by low-frequency peaks associated with the vibrations of the I3 anion. The point-contact spectra are compared with the optical reflection and absorption spectra. It is found that the nonlinearities observed in the high-voltage region are due to a significant contribution to the point-contact spectrum from the interaction between charge carriers and intermolecular vibrations. The obtained results point towards the possibility of investigating the intramolecular vibrations by the point-contact spectroscopy technique.

Перевод пока недоступен