1209.2256 (D. V. Efremov et al.)

Manifestation of impurity induced s_{+-} -> s_{++} transition: multiband
model for dynamical response functions    [PDF]

D. V. Efremov, A. A. Golubov, O. V. Dolgov

We investigate effects of disorder on the density of states, the single particle response function and optical conductivity in multiband superconductors with s_{+-} symmetry of the order parameter, where s_{+-} -> s_{++} transition may take place. In the vicinity of the transition the superconductive gapless regime is realized. It manifests itself in anomalies in the above mentioned properties. As a result, intrinsically phase-insensitive experimental methods like ARPES, tunneling and terahertz spectroscopy may be used for revealing of information about the underlying order parameter symmetry.

View original: http://arxiv.org/abs/1209.2256