Adsorption and switching properties of azobenzene derivatives on different noble metal surfaces: Au(111), Cu(111), and Au(100)

The adsorption and switching behavior of 3,3',5,5'-tetra-tert-butylazobenzene (meta-TBA) are investigated by low-temperature scanning tunneling microscopy on three different metal substrates: Au(111), Cu(111), and Au(100). The trans state is the most stable configuration after adsorption, displaying similar appearances in the STM images, independent of the substrate. However, the self-assembly and switching behavior is highly dependent on the chemistry and corrugation of the surface. On the Au(111) surface, the tip-induced isomerization is probed successfully and different driving mechanisms are characterized. The experimental images are in good agreement with calculated ones. However, the switching effect is completely suppressed on Cu(111) and Au(100).