How electrons pair in cuprate superconductors depends, in part, on the crystalline landscape the electrons occupy. That landscape can be altered by applying pressure, which in turn causes the critical temperature (Tc) in some cuprates to rise, fall, and rise again as the pressure grows. But are the changes in Tc due to the atoms being pressed into a new crystalline structure or just being squeezed closer together? Experimental evidence is contradictory. To resolve the question, Alexander Mark of the University of Illinois Chicago and his collaborators performed experiments on the three members of the BSCCO family of cuprates [1]. They showed that the pressure-induced shifts in Tc coincide with changes in how the materials compress, which in turn reflect changes in electronic structure.
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