Source: Science and technology daily
According to a recent study by the school of art and science at Cornell University, strontium ruthenate may be a new type of g-wave superconductor, according to a recent report by the Institute of Arts and Sciences of Cornell University. The results are published in the latest issue of natural physics.
In a superconductor, two electrons gather together to form a Cooper pair moving together. This "pairing" endows superconductor with its unique property zero resistance. In lead, tin, mercury and other S-wave superconductors, the electrons that form Cooper pairs have one spin up and one spin down. Their opposite spin values are considered to balance or cancel each other, so there is no angular momentum. In d-wave superconductors, the Cooper pair has double quantum angular momentum. At present, physicists have proved theoretically that there is a third kind of superconductor between the two so-called "singlet" states: the P-wave superconductor with a single quantum angular momentum. The electron pairing mode is parallel spin rather than antiparallel spin.
For more than 20 years, strontium ruthenate has been one of the main candidate materials for P-wave superconductors. So the Cornell University team set out to determine whether strontium ruthenate is an ideal P-wave superconductor. By using high-resolution resonance ultrasound spectroscopy, they found that this material may be a new superconductor: g-wave superconductor.
The team measured the response of the elastic constants of the crystal to various sound waves as the material cooled in a superconducting transition of 1.4 degrees Kelvin (- 457.87 degrees Fahrenheit). Based on these data, they determined that strontium ruthenate is a so-called two-component superconductor, which means that the way electrons are bound together is too complex to be described by a single number.
"This is the highest accuracy of resonance ultrasonic spectrum data obtained at low temperature so far." The researchers said.
The possibility of using nuclear magnetic resonance spectroscopy to narrow down the range to determine which wave superconductor strontium ruthenate may be, effectively excluding the possibility of P-wave, and also excluding the traditional S-wave or d-wave superconductor. (reporter Zhang Jiaxin, intern Zhao Xuan)
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