What do you do when you have a scanning tunnelling electron microscope (STM) and a lot of time? You borrow from the skills and techniques of Ray Harryhausen and create the smallest stop-motion movie. It’s passed the million views mark on YouTube already.
The team behind the film did some ‘proper’ scientific research proving that 12 atoms can store a memory bit. Rather than the current million or so atoms that even the smallest die-mask technologies demand. This research is the start of a long process for converting proof of ideas into viable commercial technologies. The breakthrough allows memory density to increase by orders of magnitude.
The process places carbon-monoxide molecules on a copper Cu111 base substrate. A temperature of 5K (5 degrees above absolute zero) means that the molecules stay put when moved. The electric fields generated by the tip of the STM push the molecules into place. The team could then accurately position the 63 molecules in a frame just 45nm x 25nm wide. (The frame width is 29 times and the height 52 times smaller than our own reference 1310nm light wavelength). Because of the interaction of the carbon-monoxide molecules and the copper, the oxygen portion of the molecule stands above the copper surface. The atoms positions are reported by the same electromagnetic fields that move them. The STM then scans the substrate surface to create the image of the atoms raised above the surface. The ripples seen in the image are the effects of the molecules on the electrons within the copper substrate.
But pushing atoms around is not for the faint-hearted. It took the team working 18 hour days between 29 January 2013 and 6 February 2013 to create the 242 images that became the film. At 24 frames a second and 1 minute 33 seconds long, there are an awful lot of repeated images in the film. As with most animation, the time is not putting the images together afterwards, but in creating them in the first place.
If you want to find out more about the making of the movie, IBM has coincidentally released the movie below. This provides background on how the movie was made, as well as the equipment used at IBM’s Almaden Research Centre in San Jose, California. There is also some material for STEM teachers on IBM’s Research page (A Boy And His Atom: The World’s Smallest Movie)
