Perfect rings of C60 molecules, lined up around circular layers of silver, reveal an important property of nanoelectronic contacts: thermal energy causes the structures to fluctuate. The movement of the molecules in the rings is captured by making repeated ("time-lapse") STM images. The results show that the ring vibrates like a mechanical object, with well-defined shape changes known as "modes." Such metal-molecule interface vibrations will create unique electrical signatures in nanoelectronic devices.
Molecular Nano-Rings
Top left: False color images, measured using scanning tunneling microscopy (STM), of C60 molecules arranged around the inside edge of a circular "hole" of Ag, and around a circular plateau. Individual C60 molecules are easily seen in the smaller ring at lower left, and in the zoom-in image of a segment of the edge of the ring.
Left: Illustration of the vibration modes that distort a mechanical ring, for instance a musical chime, when it vibrates to create a musical tone. Time resolved images of the molecular ring reveal the same types of modes.
UMD Materials Research Science and Engineering Center (2005)
The Maryland MRSEC carries out nationally recognized fundamental research on surfaces and interfaces of materials with potential impact on the next generation of opto- and nano-electronic devices, and on complex oxides with potential applications in memory, switches, and sensors.