Physics – Squeezing Superconductors
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• Physics 16, s85
Experiments on a household of cuprate superconductors resolve discrepancies in earlier work and elucidate why the essential temperature varies with stress.
How electrons pair in cuprate superconductors relies upon, partially, on the crystalline panorama the electrons occupy. That panorama might be altered by making use of stress, which in flip causes the essential temperature (Tc) in some cuprates to rise, fall, and rise once more because the stress grows. However are the modifications in Tc because of the atoms being pressed into a brand new crystalline construction or simply being squeezed nearer collectively? Experimental proof is contradictory. To resolve the query, Alexander Mark of the College of Illinois Chicago and his collaborators carried out experiments on the three members of the BSCCO household of cuprates [1]. They confirmed that the pressure-induced shifts in Tc coincide with modifications in how the supplies compress, which in flip mirror modifications in digital construction.
The high-pressure experiments on the superconductors have been accomplished in diamond anvil cells. The potential of conflicting outcomes arises from how the crystals reply to inhomogeneities within the compression atmosphere. If the crystal experiences shear, the stress–Tc relationship might be obscured. To take away this impact, Mark and his collaborators suspended the BSCCO crystals in neon contained in the pattern chambers of the anvil cells. They used x-ray diffraction to trace structural modifications as they elevated the stress.
The researchers discovered that the BSCCO crystals retained their orthorhombic construction as much as the best stress they utilized, 155 gigapascals. Additionally they discovered that an ordinary equation for a crystal’s quantity as a perform of stress labored provided that they break up their information into totally different regimes above and beneath a essential stress. What’s extra, the essential pressures tracked the inflection factors within the stress dependence of Tc related to modifications in digital construction. Figuring out the character of those modifications may yield insights into sensible methods of elevating Tc.
–Charles Day
Charles Day is a Senior Editor for Physics Journal.
References
- A. C. Mark et al., “Construction and equation of state of Bi2Sr2Can−1CunO2n+4+ from x-ray diffraction to megabar pressures,” Phys. Rev. Mater. 7, 064803 (2023).
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