High-temperature superconductivity in the iron pnictides

Puzzling phonon dispersion curves and vibrational mode instability in superconducting MgCNi3

“…The spectral function is different than the phonon DOS at higher energies. The present study suggests that there is not involvement of any exotic mechanism in the superconductivity in MgCNi 3 . The success of present first principles calculation in predicting the stable phonon modes and in agreement with experimental IXS measurement can be attributed to the improved computational efficiency and optimization of the geometry suggesting MgCNi 3 lies at least in its local minimum of energy.…”

“…24,29 Further the Fig. 5 reveals that the phonon DOS and α 2 F(ω) are similar in many materials, while they are remarkably different in MgCNi 3 . This nature has earlier been reported in MgB 2 30 where there are different structures in both quantities.…”

“…1 and experiment. 24 Table I summarizes the calculational scheme and their output to have a clear view on the effect of pseudopotentials on the dynamical stability on MgCNi 3 . Fig.…”

“…[1][2][3][4] The superconductivity is unusual in view of the large content of Ni in the material, which would normally favour a magnetic ground state. Thus, in the recent past several attempts have been made to investigate the structural, electronic, vibrational and superconducting properties of MgCNi 3 .…”

Superconductivity from repulsive interaction

“…In some systems, like LiFeAs [73] and LaFePO [77], superconductivity emerges already at zero doping, instead of a magnetic order. magnetism, the electronic structure, the normal state properties of FeSCs, and the interplay between FeSCs and cuprate superconductors have been reviewed in several recent publications [78,79,80,81,82,83,84,85,86,87,88,89,90,91]. Below we shall not dwell into the intricacies of the phase diagram but only focus on the superconductivity.…”