Pin It

In many metals, as the temperature drops, so does electrical resistance—but only until some threshold temperature, at which point resistance begins to increase. That puzzle can be explained by the presence of magnetic atoms in the metal. Unpaired electron spins in these impurities couple collectively with all of the metal’s free-flowing electrons to form an antiferromagnetic region called a Kondo cloud. Electrons within the cloud are impeded, increasing the material’s resistance, while the atoms’ unpaired spins are screened from their surroundings. Does the same phenomenon occur in superconductors, whose electron-pairing mechanism and many-body states are different? Paşcu Moca of the University of Oradea, Romania, in collaboration with Gergely Zaránd’s group at the Budapest University of Technology and Economics, Hungary, now provide evidence that the Kondo cloud may indeed survive in a superconductor [1].

To read more, click here.