Spin-imbalanced Fermi superfluidity in a Hubbard model on a Lieb lattice

dc.contributorAalto-yliopistofi
dc.contributorAalto Universityen
dc.contributor.authorTylutki, Mareken_US
dc.contributor.authorTörmä, Päivien_US
dc.contributor.departmentDepartment of Applied Physicsen
dc.contributor.groupauthorQuantum Dynamicsen
dc.date.accessioned2018-10-16T08:55:10Z
dc.date.available2018-10-16T08:55:10Z
dc.date.issued2018-09-17en_US
dc.description.abstractWe obtain a phase diagram of the spin-imbalanced Hubbard model on the Lieb lattice, which is known to feature a flat band in its single-particle spectrum. Using the BCS mean-field theory for multiband systems, we find a variety of superfluid phases with imbalance. In particular, we find four different types of FFLO phases, i.e., superfluid phases with periodic spatial modulation. They differ by the magnitude and direction of the center-of-mass momentum of Cooper pairs. We also see a large region of stable Sarma phase, where the density imbalance is associated with zero Cooper pair momentum. In the mechanism responsible for the formation of those phases, the crucial role is played by the flat band, wherein particles can readjust their density at zero energy cost. The multiorbital structure of the unit cell is found to stabilize the Sarma phase by allowing for a modulation of the order parameter within a unit cell. We also study the effect of finite temperature and a lattice with staggered hopping parameters on the behavior of these phases.en
dc.description.versionPeer revieweden
dc.format.extent1-10
dc.format.mimetypeapplication/pdfen_US
dc.identifier.citationTylutki, M & Törmä, P 2018, ' Spin-imbalanced Fermi superfluidity in a Hubbard model on a Lieb lattice ', Physical Review B, vol. 98, no. 9, 094513, pp. 1-10 . https://doi.org/10.1103/PhysRevB.98.094513en
dc.identifier.doi10.1103/PhysRevB.98.094513en_US
dc.identifier.issn2469-9950
dc.identifier.issn1550-235X
dc.identifier.otherPURE UUID: 78ad2ff5-bd1f-4619-9685-9b276e87fe6fen_US
dc.identifier.otherPURE ITEMURL: https://research.aalto.fi/en/publications/78ad2ff5-bd1f-4619-9685-9b276e87fe6fen_US
dc.identifier.otherPURE LINK: http://www.scopus.com/inward/record.url?scp=85053421801&partnerID=8YFLogxKen_US
dc.identifier.otherPURE FILEURL: https://research.aalto.fi/files/28341308/PhysRevB.98.094513.pdfen_US
dc.identifier.urihttps://aaltodoc.aalto.fi/handle/123456789/34291
dc.identifier.urnURN:NBN:fi:aalto-201810165368
dc.language.isoenen
dc.relation.ispartofseriesPhysical Review Ben
dc.relation.ispartofseriesVolume 98, issue 9en
dc.rightsopenAccessen
dc.titleSpin-imbalanced Fermi superfluidity in a Hubbard model on a Lieb latticeen
dc.typeA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessäfi
dc.type.versionpublishedVersion

Files