Quantum Monte Carlo study for multiorbital systems with preserved spin and orbital rotational symmetries

Abstract

We propose to combine the Trotter decomposition and a series expansion of the partition function for Hund's exchange coupling in a quantum Monte Carlo (QMC) algorithm for multiorbital systems that preserves spin and orbital rotational symmetries. This enables us to treat the Hund's (spin-flip and pair-hopping) terms, which is difficult in the conventional QMC method. To demonstrate this, we first apply the algorithm to study ferromagnetism in the two-orbital Hubbard model within the dynamical mean-field theory (DMFT). The result reveals that the preservation of the SU(2) symmetry in Hund's exchange is important, where the Curie temperature is grossly overestimated when the symmetry is degraded, as is often done, to Ising (Z${}_2$). We then calculate the $t_{2g}$ spectral functions of Sr${}_2$RuO${}_4$ by a three-band DMFT calculation with tight-binding parameters taken from the local density approximation with proper rotational symmetry.

9 pages, 9 figures. Typos corrected, some comments and references added

References in corpus (8)

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Cited by in corpus (8)

• High-spin to low-spin and orbital polarization transitions in multiorbital Mott systems
• Subband filling and Mott transition in Ca_{2-x}Sr_xRuO_4
• Doped Mott insulator as the origin of heavy Fermion behavior in LiV2O4
• Exact Diagonalization Dynamical Mean Field Theory for Multi-Band Materials: Effect of Coulomb correlations on the Fermi surface of Na_0.3CoO_2
• Electronic structure and effects of dynamical electron correlation in ferromagnetic bcc-Fe, fcc-Ni and antiferromagnetic NiO
• Itinerant ferromagnetism in the multiorbital Hubbard model: a dynamical mean-field study
• Metal-insulator transition in the two-orbital Hubbard model at fractional band fillings: Self-energy functional approach
• Influence of Band and Orbital Degeneracies on Ferromagnetism in the Periodic Anderson Model