Electronic compressibility in iron-based superconductors enhanced by Hund's coupling

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Date/Time:Thursday, 13 Feb 2020 from 4:10 pm to 5:00 pm
Location:Physics 3
Channel:Condensed Matter Physics
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Pablo Villar Arribi (Argonne)

FeSe (both bulk and monolayer), LiFeP, LiFeAs and NaFeAs have been studied computationally treating dynamical electronic correlations explicitly within a slave-spin mean-field + density-functional theory scheme. A zone of enhancement of the electronic compressibility has been found in the interaction-doping phase diagram of these compounds in accord with the phenomenology of Hund's metals (that will be briefly introduced). This enhanced electronic compressibility may have an important influence in superconductivity and it has been previously found in simulations of simplified models and of the so-called 122 family of iron-based superconductors (IBSC) [1]. We now find a similar enhancement in these other families of IBSC, but more importantly, its evolution along the interaction-doping phase diagram correlates positively with the experimental trends seen for TC as a function of hydrostatic pressure in the case of FeSe [2], and as a function of hydrostatic pressure and different chemical substitutions in the case of LiFeP, LiFeAs and NaFeAs [3]. These findings support the possibility that Hund's-coupling induced many-body correlations boost superconductive pairing when the system is at the frontier between a normal and a Hund's metal.