Now, in a paper published online in the journal Nature Nanotechnology, the Stanford researchers describe how they have created letters 40 times smaller than the original prize-winning effort and more than four times smaller than the IBM initials. (http://www.youtube.com/watch?v=j3QQJEHuefQ)
Working in a vibration-proof basement lab in the Varian Physics Building, Manoharan and Moon began their writing project with a scanning tunneling microscope, a device that not only sees objects at a very small scale but also can be used to move around individual atoms. The Stanford team used it to drag single carbon monoxide molecules into a desired pattern on a copper chip the size of a fingernail.
On the two-dimensional surface of the copper, electrons zip around, behaving as both particles and waves, bouncing off the carbon monoxide molecules the way ripples in a shallow pond might interact with stones placed in the water.
The ever-moving waves interact with the molecules and with each other to form standing "interference patterns" that vary with the placement of the molecules.
By altering the arrangement of the molecules, the researchers can create different waveforms, effectively encoding information for later retrieval. To encode and read out the data at unprecedented density, the scientists have devised a new technology, Electronic Quantum Holography.
In a traditional hologram, laser light is shined on a two-dimensional image and a ghostly 3-D object appears. In the new holography, the two-dimensional "molecular holograms" are illuminated not by laser light but by the electrons that are already in the copper in great abundance. The resulting "electronic object" can be read with the scanning tunneling microscope.
Several images can be stored in the same hologram, each created at a different elect
|Contact: Dan Stober|