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arXiv:1707.04313 · Physical review. B./Physical review. B

Density matrix renormalization group study of a three-orbital Hubbard model with spin-orbit coupling in one dimension

Nitin Kaushal, J. Herbrych, Alberto Nocera, Gonzalo Álvarez, Adriana Moreo, Fernando Agustín Reboredo, Elbio R. Dagotto

Published Oct 9, 2017• 24 citations
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Abstract

Using the density matrix renormalization group technique we study the effect of spin-orbit coupling on a three-orbital Hubbard model in the ${({t}_{2g})}^{4}$ sector and in one dimension. 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 $\ensuremath{\lambda}$, at zero temperature. Our results are shown to be qualitatively similar to those recently reported using the dynamical mean-field theory in higher dimensions, providing a robust basis to approximate many-body techniques. Among many results, we observe an interesting transition from an orbital-selective Mott phase to an excitonic insulator with increasing $\ensuremath{\lambda}$ at intermediate $U$. In the strong $U$ coupling limit, we find a nonmagnetic insulator with an effective angular momentum $\ensuremath{\langle}{({\mathbf{J}}^{\mathrm{eff}})}^{2}\ensuremath{\rangle}\ensuremath{\ne}0$ near the excitonic phase, smoothly connected to the $\ensuremath{\langle}{({\mathbf{J}}^{\mathrm{eff}})}^{2}\ensuremath{\rangle}=0$ regime. We also provide a list of quasi-one-dimensional materials where the physics discussed in this paper could be realized.

DOI
10.1103/physrevb.96.155111

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