Superconductivity in multiorbital systems with repulsive interactions: Hund's pairing versus spin-fluctuation pairing
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Superconductivity in multiorbital systems with repulsive interactions : Hund's pairing versus spin-fluctuation pairing. / Roig, Merce; Romer, Astrid T.; Kreisel, Andreas; Hirschfeld, P. J.; Andersen, Brian M.
I: Physical Review B, Bind 106, Nr. 10, 100501, 09.09.2022.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Superconductivity in multiorbital systems with repulsive interactions
T2 - Hund's pairing versus spin-fluctuation pairing
AU - Roig, Merce
AU - Romer, Astrid T.
AU - Kreisel, Andreas
AU - Hirschfeld, P. J.
AU - Andersen, Brian M.
PY - 2022/9/9
Y1 - 2022/9/9
N2 - Hund's pairing refers to Cooper pairing generated by onsite interactions that become attractive due to large Hund's exchange J. This is possible in multiorbital systems even when all local bare interactions are repulsive, since attractions in specific channels are given by certain linear combinations of interaction parameters. On the other hand, pairing processes such as the exchange of spin fluctuations are also present. We compare mean-field Hund's pairing and spin-fluctuation-mediated pairing using electronic bands appropriate for different classes of multiorbital systems over a wide range of interaction parameters. We find that, for systems without clear nesting features, the superconducting state generated by the Hund's mechanism agrees well with that from the full fluctuation exchange vertex when Hund's exchange and spin-orbit coupling are sufficiently large. On the other hand, for systems characterized by a peaked finite-momentum particle-hole susceptibility, spin-fluctuation pairing generally dominates over Hund's pairing. From this perspective Hund's pairing states appear unlikely to be realized in systems like Sr2RuO4 and generic iron-based superconductors.
AB - Hund's pairing refers to Cooper pairing generated by onsite interactions that become attractive due to large Hund's exchange J. This is possible in multiorbital systems even when all local bare interactions are repulsive, since attractions in specific channels are given by certain linear combinations of interaction parameters. On the other hand, pairing processes such as the exchange of spin fluctuations are also present. We compare mean-field Hund's pairing and spin-fluctuation-mediated pairing using electronic bands appropriate for different classes of multiorbital systems over a wide range of interaction parameters. We find that, for systems without clear nesting features, the superconducting state generated by the Hund's mechanism agrees well with that from the full fluctuation exchange vertex when Hund's exchange and spin-orbit coupling are sufficiently large. On the other hand, for systems characterized by a peaked finite-momentum particle-hole susceptibility, spin-fluctuation pairing generally dominates over Hund's pairing. From this perspective Hund's pairing states appear unlikely to be realized in systems like Sr2RuO4 and generic iron-based superconductors.
U2 - 10.1103/PhysRevB.106.L100501
DO - 10.1103/PhysRevB.106.L100501
M3 - Journal article
VL - 106
JO - Physical Review B
JF - Physical Review B
SN - 2469-9950
IS - 10
M1 - 100501
ER -
ID: 321269504