Vertical Tunnel Junction Embedding a Spin Crossover Molecular Film

Thin films of a molecular spin crossover (SCO) Iron(II) complex featuring a high transition temperature are grown by sublimation in high vacuum on Au-TS and investigated by X-ray and UV photoelectron spectroscopies. Temperature-dependent studies demonstrate that the thermally induced spin crossover behavior is preserved in thin films. A large-area ultrathin switchable spin crossover molecular vertical tunnel junction with top electrodes of the liquid eutectic of gallium and indium, for which the spin-state switching of the films induces a two orders of magnitude change in the tunneling current density flowing through the junction, is reported here. The results on large-area junctions, rationalized by density functional theory calculations, demonstrate the high potential of SCO-based switchable molecular junctions as functional devices.