Hidden Symmetries and Their Consequences in t2g Cubic Perovskites

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dc.contributor.authorHarris, A. Brooks
dc.contributor.authorYildirim, Tanner
dc.contributor.authorAharony, Amnon
dc.contributor.authorEntin-Wohlman, Ora
dc.contributor.authorKorenblit, I. Ya
dc.date2023-05-17T12:07:01.000
dc.date.accessioned2023-05-23T00:24:50Z
dc.date.available2023-05-23T00:24:50Z
dc.date.issued2004-01-22
dc.date.submitted2015-08-06T08:04:19-07:00
dc.description.abstractThe five-band Hubbard model for a d band with one electron per site is a model which has very interesting properties when the relevant ions are located at sites with high (e.g., cubic) symmetry. In that case, if the crystal-field splitting is large, one may consider excitations confined to the lowest threefold-degenerate t2g orbital states. When the electron hopping matrix element (t) is much smaller than the on-site Coulomb interaction energy (U), the Hubbard model can be mapped onto the well-known effective Hamiltonian (at order t2/U) derived by Kugel and Khomskii (KK). Recently we have shown that the KK Hamiltonian does not support long-range spin order at any nonzero temperature due to several novel hidden symmetries that it possesses. Here we extend our theory to show that these symmetries also apply to the underlying three-band Hubbard model. Using these symmetries we develop a rigorous Mermin-Wagner construction, which shows that the three-band Hubbard model does not support spontaneous long-range spin order at any nonzero temperature and at any order in t/U—despite the three-dimensional lattice structure. The introduction of spin-orbit coupling does allow spin ordering, but even then the excitation spectrum is gapless due to a subtle continuous symmetry. Finally we show that these hidden symmetries dramatically simplify the numerical exact diagonalization studies of finite clusters.
dc.description.commentsAt the time of publication, author Taner Yildirim was affiliated with the National Institute of Standards and Technology, Gaithersburg, Maryland. Currently, he is a faculty member in the Materials Science and Engineering Department at the University of Pennsylvania.
dc.identifier.urihttps://repository.upenn.edu/handle/20.500.14332/43044
dc.legacy.articleid1428
dc.legacy.fields10.1103/PhysRevB.69.035107
dc.legacy.fulltexturlhttps://repository.upenn.edu/cgi/viewcontent.cgi?article=1428&context=physics_papers&unstamped=1
dc.source.beginpage035107-1
dc.source.endpage035107-11
dc.source.issue335
dc.source.journalDepartment of Physics Papers
dc.source.journaltitlePhysical Review B
dc.source.peerreviewedtrue
dc.source.statuspublished
dc.source.volume69
dc.subject.otherPhysics
dc.titleHidden Symmetries and Their Consequences in t2g Cubic Perovskites
dc.typeArticle
digcom.contributor.authorisAuthorOfPublication|email:harris@sas.upenn.edu|institution:University of Pennsylvania|Harris, A. Brooks
digcom.contributor.authorisAuthorOfPublication|email:taner@seas.upenn.edu|institution:University of Pennsylvania|Yildirim, Tanner
digcom.contributor.authorAharony, Amnon
digcom.contributor.authorEntin-Wohlman, Ora
digcom.contributor.authorKorenblit, I. Ya
digcom.identifierphysics_papers/335
digcom.identifier.contextkey7421989
digcom.identifier.submissionpathphysics_papers/335
digcom.typearticle
dspace.entity.typePublication
relation.isAuthorOfPublication2bfc1be9-8e1a-4190-9cd7-2f49b510869e
relation.isAuthorOfPublication80f96ce1-bb5b-45c3-99af-78d36747185b
relation.isAuthorOfPublication.latestForDiscovery2bfc1be9-8e1a-4190-9cd7-2f49b510869e
upenn.schoolDepartmentCenterDepartment of Physics Papers
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