On a more realistic front, room-temperature superconductivity, one of physics' Holy Grails, might be within reach in a decade or two. (Sorry, have to be a subscriber to read it all.) Magnesium diboride is the key.
Last year, [Warren] Pickett decided to go back to basics and re-examine the theory, inspired by an astonishing discovery reported in 2001 by Jun Akimitsu's team at Aoyama Gakuin University in Tokyo. Akimitsu and his colleagues were playing around with mixtures of titanium, magnesium and boron in an attempt to find a new superconductor. To their surprise, they stumbled across hints of superconductivity at 40 K....430 K is over 314 degrees Fahrenheit, an incredible temperature, hundreds of degrees (on any scale) hotter than present technology. Pickett, to his credit, hasn't made any unverifiable promises or formed a startup company to lure investors with dreams of glory. We'll just have to wait for the revolution.
The finding was scientific dynamite. Within two months of Akimitsu's announcement, 50 papers were published online as researchers rushed to study magnesium diboride for themselves....
Pickett realised that if he could identify what made magnesium diboride so special, other metal alloys might be found with even higher critical temperatures. To do this, he studied what affected the critical temperature in Bardeen, Cooper and Schrieffer's studies and then compared these factors to the properties of magnesium diboride.
According to their theory, the critical temperature depends on three things: the number of electrons available, the frequency at which the phonons vibrate, and the strength of the interaction or "coupling" between the phonons and electrons. Magnesium diboride's high transition temperature is due mostly to strong coupling, which is down to its chemical structure. It consists of layers of boron just one atom thick sandwiched between layers of magnesium atoms.... Each magnesium atom feeds two electrons into the boron layers, which means that there are abundant electrons in the structure.... [T]he electrons flow in the same layer as the boron atoms and set up large disturbances, which enhance the coupling between phonons and electrons as they sweep through the material. The upshot is that the electron-pairing still takes place at higher temperatures than expected.
Despite the strong interaction between phonons and electrons... only 3 per cent of phonons interact at all. "Impressive as it is, magnesium diboride is doing a poor job of making use of the available phonons," says Pickett. "If we could use most of the phonons, the critical temperature would increase all the way past room temperature...."
[H]e proposes involving more phonons by trying different combinations of elements. What's more, his blueprint gives researchers clues as to which elements would work best, rather than resorting to trial and error as they have done in the past. By doing this, his calculations show that it should be possible to find a material that superconducts at a searing 430 K...."