Dresden 2026 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 95: Fe-based Superconductors
TT 95.5: Vortrag
Freitag, 13. März 2026, 10:30–10:45, HSZ/0103
Intertwined superconductivity and orbital selectivity in a three-orbital Hubbard model for the iron pnictides — Vito Marino1,2, Alberto Scazzola2, Federico Becca3, Massimo Capone1, and •Luca F. Tocchio2 — 1International School for Advanced Studies (SISSA), Trieste, Italy — 2Politecnico di Torino, Italy — 3University of Trieste, Italy
We study a three-orbital Hubbard-Kanamori model relevant for iron-based superconductors, using variational wave functions which explicitly include spatial correlations and electron pairing. We span the nonmagnetic sector from filling n = 4, which is representative of undoped iron-based superconductors, to n = 3, where a Mott insulating state with each orbital at half filling is found. In the strong-coupling regime, we observe spontaneous differentiation in the occupation of the dxz and dyz orbitals, leading to an orbital-selective state with nematic character that becomes stronger with increasing density. One of these orbitals remains half-filled for all densities, while the other hosts (together with the dxy orbital) the excess electron density. Most importantly, in this regime, long-range pairing correlations appear in the orbital with the largest occupation. Our results highlight a strong link between orbital-selective correlations, nematicity, and superconductivity, which requires the presence of a significant Hund’s coupling. The interplay with magnetism is also discussed.
[1] V. Marino, A. Scazzola, F. Becca, M. Capone, and L.F. Tocchio, PRL 134, 196502 (2025).
Keywords: Iron-based superconductors; High-temperature superconductivity; Hubbard model; Variational Monte Carlo; Nematic order