报告题目（Title）：Tip-induced manipulation of a molecule’s adsorption potential probed by the switching directionality
报 告 人（Speaker）：Prof. Mikhail Fonin (德国康斯坦茨大学)
报告时间（Time）： 2019年9月24日（周二）16：00
报告地点（Place）：校本部E106
邀请人（inviter）：Prof. Elena Voloshina
摘要（Abstract）：
The switching behaviour of surface-supported molecular units excited by current, light or mechanical forces is determined by the shape of the adsorption potential. The ability to tailor the energy landscape that a molecule resides in at a surface gives a possibility to impose a desired response, which is of paramount importance for the realization of molecular electronic units. In my talk I will focus on a system consisting of a triazatruxene (TAT) molecule on Ag(111). By using scanning tunneling microscopy we show that TAT exhibits a switching behavior characterized by transitions of the molecule between three states, and which we attribute to three energetically degenerate bonding configurations. Upon tunneling current injection the system can be excited, showing a pronounced switching directionality. Two surface enantiomers of TAT show opposite switching directions pointing at the chirality of the energy landscape of the adsorption potential as a key indigent for directional switching. Further we show that by modifying the tunneling parameters, the symmetry of the adsorption potential can be controlled, leading to a suppression of the directionality or an inversion of the switching direction. Our findings represent a molecule-surface model system exhibiting unprecedented control of the shape of its adsorption potential.
