Nano Focus: Directional molecular motor rotation electrically driven
- PDF / 1,507,657 Bytes
- 4 Pages / 585 x 783 pts Page_size
- 52 Downloads / 233 Views
aid in the development of artificial multiferroic tunnel barriers and novel spintronic memories, as well as new kinds of coupled ferroic order. Steven Spurgeon
Magnetoelectric character can also be induced in BTO at room temperature, mediated by a spin-polarized bonding effect on interfacial Ti4+ ions. The researchers said that their findings may
Nano Focus Directional molecular motor rotation electrically driven
A
research team from Tufts University has demonstrated the first known example of directional molecular rotation driven by electricity. While there are a number of examples of socalled molecular motors driven by light or a chemical reaction, this latest device described in the October issue of Nature Nanotechnology (DOI: 10.1038/ NNANO.2011.142; p. 625) uses as impetus the electric current supplied by a scanning tunneling microscope (STM). H. Tierney, C. Sykes, and co-workers
An example of a current versus time spectrum that provides a way of monitoring the rotation of butyl methyl sulfide between six different orientations shown in the schematic (top right). A model of the molecule on the Cu(111) surface is shown at bottom right. Reproduced with permission from Nature Nanotech. 6 (2011), DOI: 10.1038/NNANO.2011.142; p. 625. © 2011 Macmillan Publishers.
Booth #100 Please join us…
FREE.
Join the Materials Today and Elsevier team every afternoon, during afternoon break, for our exclusive meet and greet events.
Go on: Take it… Subscribe today to Materials Today, the international review magazine for the materials research and development community.
www.materialstoday.com/magazine-subscription
Light refreshments will be served!
Visit us at the MRS Fall Meeting and Exhibit: Booth #100
MRS BULLETIN
We will also be announcing the winners of the annual Materials Today cover competition.
•
VOLUME 36 • NOVEMBER 2011
•
www.mrs.org/bulletin
845
NEWS & ANALYSIS RESEARCH/RESEARCHERS looked at molecules of butyl methyl sulfide (BuSMe) which, when absorbed on a Cu(111) surface, rotate about the metal– sulfur bond in hops of 60 degrees. The group’s previous work on these thioether rotors has shown that the rotation can be driven using a STM tip to electrically excite molecular vibrations which couple to rotational modes. In the current study, placing the tip to one side of the sulfur fulcrum allows the six discrete positions that the molecule adopts on the surface to be distinguishable by different tunneling currents. In this way, the size and direction of each hop taken by the rotating molecule is revealed, along with any directional bias. Without any electrical excitation from the tip, but with thermal energy provided by operating at 8 K, the
www.mrs.org/africa-2011
molecule rotated in a random fashion as expected. When driven by current from the microscope tip, rotation was considerably slower (around 30 Hz) but showed up to 5% bias toward one direction. Depending on which of the sulfur lone pairs binds to the metal surface, the bound thioether can exhibit two enantiomeric forms that were found to
Data Loading...
