Dresden 2017 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 70: Superconductivity: Fe-based Superconductors - Theory

TT 70.11: Talk

Thursday, March 23, 2017, 18:00–18:15, HSZ 103

Chromium analogues of iron-based supercondictors — •Martin Edelmann¹, Giorgio Sangiovanni¹, Massimo Capone², and Luca de’ Medici³ — ¹Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany — ²International School for Advanced Studies (SISSA), Via Bonomea 265, I-34136 Trieste, Italy — ³European Synchrotron Radiation Facility, 71 Av. des Martyrs, Grenoble, France

The present talk encompasses the results of our studies of BaCr₂As₂, the Cr equivalent of the 122 iron-based superconductor (FeSC) BaFe₂As₂. In the respective compound, Cr nominally hosts 4 electrons in its d orbitals, whereas Fe hosts six, placing Cr on the other side of half-filling. Therefore, one expects behaviour of the Cr compound that is specular to BaFe₂As₂. We conducted DFT+DMFT studies on the PM and G-type AFM phase as well as slave-spin mean field (SSMF) calculations on the PM phase [1]. We show that dynamical correlations are necessary to narrow the discrepancy between the Sommerfeld coefficient as accessed by theoretical studies and the experimental value. Through SSMF one finds that the BaCr₂As₂ mirrors the BaFe₂As₂ compressibility, where the BaCr₂As₂ compound phase diagram displays a crossover from a weakly to a strongly correlated metal. We infer that, similar to BaFe₂As₂, BaCr₂As₂ can be pushed into the SC regime with the proper amount of electron doping and/or negative pressure, introducing a new, interesting family of SCs.

[1] M. Edelmann, G. Sangiovanni, M. Capone, L. de’ Medici, arXiv:1610.10054