Switching Molecular Orientation of Individual Fullerene at Room Temperature

Reversible molecular switches with molecular orientation as the information carrier have been achieved on individual fullerene molecules adsorbed on Si (111) surface at room temperature. Scanning tunneling microscopy imaging directly demonstrates that the orientation of individual fullerene with an adsorption geometry of 5-6 bond is rotated by integral times as 30 degree after a pulse bias is applied between the STM tip and the molecule. Dependences of the molecular rotation probability on the voltage and the process of applied bias reveal that the rotation of a fullerene molecule takes place in two successive steps: the bonding between the fullerene and the Si surface is firstly weakened via electronic excitation and then low energy electron bombardment causes the molecule to rotate by certain degree.