New View of SuperconductivityCategory: Science & Technology
Posted: May 31, 2012 05:22PM
The ultimate goal for many materials scientists and the field of electronics is the creation of room-temperature superconductors. These, thus far, undiscovered material are able to carry electric currents with no resistance and no energy loss, like their low temperature brethren. The key to this ability is the formation of Cooper pairs, which scientists do not fully understand at the moment. Researchers at Berkeley Lab have recently done an interesting experiment to see how Cooper pairs form, and this research may lead to a new understanding of the pairs.
Cooper pairs are, essentially, electrons that have overcome their usual electromagnetic repulsion so they may travel together. In this coupled state the electrons have less energy than they would separately, but this energy they keep as they travel, which is what makes a material a superconductor.
To understand how the Cooper pairs form, the researchers decided to break some up using a pump-probe technique. An initial pumping laser pulse hits the Cooper pair, causing it to split into two higher energy quasiparticles which the probing laser pulse interacts with. The probing laser pulse captures some information from these quasiparticles, including their momentum and energy. The data show the momentum of the quasiparticles and the energy of the pumping pulse influence how quickly the Cooper pair reforms. This could be an indication of what keeps the pairs together.
Naturally, further study has to be done. Only one high temperature superconductor was used for this study, and likely the researchers will want to use additional samples. Also the light sourced used for this test is only able to produce low energy pulses. For this experiment though, that limit proved useful as it allowed for better momentum resolution. Future experiments will likely want to explore other, potentially more intriguing, energy levels however.