Origin of superconductivity in Ni-doped SrFe_2As_2 , an Insight from DMFT

Abstract

I describe the issues of the competing orders in normal state of a parent and Ni-doped iron pnictide superconductor, SrF e 2 As 2 , using LMTO band structure calculation plus multi orbital dynamical mean-field theory. Strong, electronic correlations along with minimal antiferromagnetic instability create a partially gapped Fermi surface, in qualitative agreement with earlier experiments. A good semiquantitative similarity in both normal and ordered state with the earlier experimental transport data is observed along with suppression of magnetic ordering and explained within a correlated, mul- tiorbital viewpoint. These results suggest that soft electronic fluctuation mediate superconductivity in broad class of parent and underdoped 122 pnictides with suppression of magnetic ordering.