A sheet of paper hundreds of times thinner than a human hair: that's roughly the thickness of the vanadium oxide film scientists grew. Inside this film, electrons, the tiny carriers of electric current, move almost without collisions. Like cars on an empty night highway, they accelerate and don't lose speed.
To understand how this happens, researchers cooled the film to minus 269 degrees Celsius and placed it in a strong magnetic field. Under these conditions, electrons began to move in spirals, and their paths could be measured. It turned out that the film has three types of "lanes" for electrons: two fast and one slow. On one of the fast lanes, electrons fly especially freely: their collision-free path is 20 times longer than the film's thickness.
Such freedom of movement is rare for thin films. Usually, surface roughness and internal defects slow electrons down, like potholes on a road. But in this film, grown layer by layer, near-perfect smoothness was achieved. So electrons behave just as they do in expensive single crystals that take years to grow.
This discovery brings us closer to the transparent electronics of the future: screens built into windows and flexible displays. If we learn to make such films on a mass scale, we could wear electronics like clothing and see through it as through ordinary glass.
The film's thickness in the experiment is 38 nanometers. That's about 2000 times thinner than a human hair. To stack such films to the height of a coin, you'd need about 30,000 layers.
In the series 'The Expanse', transparent screens on helmets and ship windows work precisely on thin conducting films, like the one studied by the paper's authors.