Bismuth crystals can act as superconductors — but only at temperatures approaching absolute zero.
Researchers have long been searching for new superconducting materials, which have the ability to maintain an electric current with no power source. A team led by Srinivasan Ramakrishnan at the Tata Institute of Fundamental Research in Mumbai, India, showed that bismuth crystals become superconducting if they are brought down to 0.5 millikelvin. This extreme cooling is necessary because, unlike other superconductors, bismuth has a very low density of charge carriers, with just 1 electron per 100,000 atoms.
The standard theory of superconductivity can explain the phenomenon in other metals, such as lead and aluminium, but not in bismuth, so further study is needed, the authors say.
Science http://doi.org/bvbj (2016)