Decisive proofs of the $s_{\pm }\to s_{++}$ transition in the temperature dependence of the magnetic penetration depth

V. A. Shestakov, M. M. Korshunov, Yu. N. Togushova +1

One of the features of the unconventional $s_{\pm }$ state in iron-based superconductors is possibility to transform to the $s_{++}$ state with the increase of the nonmagnetic disorde…