Quantum Phase Transitions in a Multi-orbital Hubbard Model with Spin-Orbit Coupling

ORAL

Abstract

We used the density matrix renormalization group technique to perform a detailed study of the effect of spin-orbit coupling on a three-orbital Hubbard model in one dimension [1]. Fixing the Hund coupling to a robust value compatible with some multiorbital materials, we present the phase diagram varying the Hubbard U and spin-orbit coupling λ, at zero temperature for n=4 [2]. We also present the doping and spin-orbit coupling λ phase diagram, for intermediate and strong Hubbard U [3]. Among many results, we observe an interesting transition from an orbital-selective Mott phase to an excitonic insulator with increasing λ at intermediate U. In the strong U coupling limit, we find a nonmagnetic insulator with an effective angular momentum〈(Jeff)2〉≠0 near the excitonic phase, smoothly connected to the 〈(Jeff)2〉= 0 regime. In the same model we also found a novel and robust excitonic insulator phase with Block spin ordering, at various dopings and in both the intermediate and strong coupling region.
[1] J. Rincon et. al. Phys. Rev. Lett. 112, 106405 (2014)
[2] N. Kaushal et. al. Phys. Rev. B 96, 155111(2017)
[3] N. Kaushal et. al. unpublished

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Presenters

  • Nitin Kaushal

    Department of Physics and Astronomy, Univ of Tennessee, Knoxville, University of Tennessee

Authors

  • Nitin Kaushal

    Department of Physics and Astronomy, Univ of Tennessee, Knoxville, University of Tennessee

  • Jacek Herbrych

    Department of Physics and Astronomy, Univ of Tennessee, Knoxville, University of Tennessee, Department of Physics and Astronomy, The University of Tennessee

  • Alberto Nocera

    Univ. of Tennessee, Physics and Astronomy, University of Tennessee, Department of Physics and Astronomy, Univ of Tennessee, Knoxville, University of Tennessee

  • Gonzalo Alvarez

    Oak Ridge National Laboratory, Oak Ridge National Lab, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory

  • Adriana Moreo

    Univ. of Tennessee, Department of Physics and Astronomy, Univ of Tennessee, Knoxville, Univ of Tennessee and ORNL., University of Tennessee, Univ of Tennessee, Knoxville, Department of Physics and Astronomy, University of Tennessee, Knoxville

  • Fernando Reboredo

    Oak Ridge National Lab, Materials Science and Technology Division, Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge National Lab

  • Elbio Dagotto

    Univ. of Tennessee, Physics and Astronomy, University of Tennessee, Department of Physics and Astronomy, Univ of Tennessee, Knoxville, Department of Physics and Astronomy, University of Tennessee, University of Tennessee, University of Tennessee & Oak Ridge National Laboratory, Department of Physics and Astronomy, University of Tennessee, Knoxville