Elastic electron tunneling study of the metal-insulator transition in TTF-TCNQ

Using a single crystal of TTF-TCNQ as a moving electrode and by approaching to to an oxidized Al counter-electrode we realized tunnel junctions in the temperature range of about 30 to 295 K. By selecting junctions with minimum thermionic background current and measuring the tunnel conductance by a standard constant voltage lock-in detection we observed a deepening of the zero bias conductance abruptly reaching zero at about 53 K. We suggest that this reflects a progressive depletion of the electron density of states at the Fermi level and gives a direct image of the opening of a Peierls gap at the transition temperature. © 1981.SCOPUS: ar.j