Explaining Mercury’s Superconductivity, 111 Years Later

In 1911, physicist Heike Kamerlingh Onnes used liquid helium—whose manufacturing methodology he invented—to chill mercury to a couple kelvins, discovering that its electrical resistance dropped to nil. Though mercury was later discovered to be a “standard” superconductor, no microscopic principle to this point managed to completely clarify the steel’s conduct and to foretell its important temperature T_C. Now, 111 years after Kamerlingh Onnes’ discovery, theorists have carried out simply that. Their first-principles calculations precisely predict mercury’s T_C but in addition pinpoint theoretical caveats that would inform searches for room-temperature superconductors [1].

Mercury is an exception amongst standard superconductors, most of which will be efficiently described with state-of-the-art density-functional-theory strategies. To sort out mercury’s distinctive challenges, Gianni Profeta of the College of L’Aquila, Italy, and colleagues scrutinized all bodily properties related for standard superconductivity, which is mediated by the coupling of electrons to phonons. Specifically, the researchers accounted for beforehand uncared for relativistic results that alter phonon frequencies, they improved the outline of electron-correlation results that modify digital bands, and so they confirmed that mercury’s d-electrons present an anomalous screening impact that promotes superconductivity by lowering Coulomb repulsion between superconducting electrons. With these enhancements, their calculations delivered a T_C prediction for mercury solely 2.5% decrease than the experimental worth.

The brand new understanding of the oldest superconductor will discover a place in textbooks however can also supply worthwhile classes for superconductivity analysis, says Profeta. A promising material-by-design strategy includes “high-throughput” computations that display screen thousands and thousands of theoretical materials combos to recommend people who may very well be standard superconductors near ambient situations. “If we don’t embrace delicate results just like these related for mercury, these computations could overlook many fascinating supplies or err of their important temperature predictions by lots of of kelvins,” he says.

–Matteo Rini

Matteo Rini is the Editor of Physics Journal.

Associated Articles

Extra Articles