MIT Tunes Ions For Frictionless Surface - Superlubricity!
MIT scientists have developed an experimental technique to simulate friction at the nanoscale. In particular, they can cause superlubricity - a phenomenon in which friction goes to zero, allowing surfaces to slide without resistance.
(MIT method for frictionless surface study)
Using their technique, the researchers are able to directly observe individual atoms at the interface of two surfaces and manipulate their arrangement, tuning the amount of friction between the surfaces. By changing the spacing of atoms on one surface, they observed a point at which friction disappears.
The team simulated friction at the nanoscale by first engineering two surfaces to be placed in contact: an optical lattice, and an ion crystal.
The optical lattice was generated using two laser beams traveling in opposite directions, whose fields add up to form a sinusoidal periodic pattern in one dimension. This so-called optical lattice is similar to an egg carton..
Vuletic then engineered a second surface: an ion crystal — essentially, a grid of charged atoms — in order to study friction’s effects, atom by atom. To generate the ion crystal, the group used light to ionize, or charge, neutral ytterbium atoms emerging from a small heated oven, and then cooled them down with more laser light to just above absolute zero. The charged atoms can then be trapped using voltages applied to nearby metallic surfaces...
The team then used the same forces that are used to trap the atoms to push and pull the ion crystal across the lattice, as well as to stretch and squeeze the ion crystal, much like an accordion, altering the spacing between its atoms.
...something happened to the front steps under him. They became slicker than the smoothest ice...
Every time he applied a horizontal component of force to a hand or knee, the hand or knee simply slid backward.
"...My telelubricator here neutralizes the interatomic bonds the surface of any solid on which the beam falls. So the surface, to the depth of a few molecules, is put in the condition of a supercooled liquid as long as the beam is focused on it. Since the liquid form of any compound will wet the solid form, you have perfect lubrication."
(Read more about de Camp's telelubricator)