Novel Block Excitonic Condensate at $n=3.5$ in a Spin-Orbit Coupled $t_{2g}$ Multiorbital Hubbard Model

Abstract

Theoretical studies recently predicted the condensation of spin-orbit excitons at momentum $q$=$\pi$ in $t_{2g}^4$ spin-orbit coupled three-orbital Hubbard models at electronic density $n=4$. In parallel, experiments involving iridates with non-integer valence states for the Ir ions are starting to attract considerable attention. In this publication, using the density matrix renormalization group technique we present evidence for the existence of a novel excitonic condensate at $n=3.5$ in a one-dimensional Hubbard model with a degenerate $t_{2g}$ sector, when in the presence of spin-orbit coupling. At intermediate Hubbard $U$ and spin-orbit $\lambda$ couplings, we found an excitonic condensate at the unexpected momentum $q$=$\pi /2$ involving $j_{\text{eff}}=3/2,m=\pm 1/2$ and $j_{\text{eff}}=1/2,m=\pm 1/2$ bands in the triplet channel, coexisting with an also unexpected block magnetic order. We also present the entire $\lambda$ vs $U$ phase diagram, at a fixed and robust Hund coupling. Interestingly, this new `block excitonic phase' is present even at large values of $\lambda$, unlike the $n=4$ excitonic phase discussed before. Our computational study helps to understand and predict the possible magnetic phases of materials with $d^{3.5}$ valence and robust spin-orbit coupling.

References in corpus (18)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Magnetism and its microscopic origin in iron-based high-temperature superconductors
• Microscopic study of spin-orbit-induced Mott insulator in Ir oxides
• Excitonic quasiparticles in a spin-orbit Mott insulator
• Testing the validity of the strong spin-orbit-coupling limit for octahedrally coordinated iridates in a model system Sr${}_3$CuIrO${}_6$
• Spectral Functions with the Density Matrix Renormalization Group: Krylov-space Approach for Correction Vectors
• Effective magnetic interactions in spin-orbit coupled $d^4$ Mott insulators
• CaIrO3 post-perovskite, a j = 1/2 quasi-one-dimensional antiferromagnet
• J-freezing and Hund's rules in spin-orbit-coupled multiorbital Hubbard models
• Non-local correlations in the orbital selective Mott phase of a one dimensional multi-orbital Hubbard model
• Engineering One-Dimensional Quantum Stripes from Superlattices of Two-Dimensional Layered Materials
• Density matrix renormalization group study of a three-orbital Hubbard model with spin-orbit coupling in one dimension
• Quantum phase transition between orbital-selective Mott states in Hund's metals
• Spin-orbit-induced exotic insulators in a three-orbital Hubbard model with $(t_{2g}{)}^5$ electrons
• Optical Signatures of Spin-Orbit Exciton in Bandwidth Controlled Sr${}_2$IrO${}_4$ Epitaxial Films via High-Concentration Ca and Ba Doping
• Structural evolution and electronic properties of (Sr1-xCax)2-yIrO4+z spin-orbit assisted insulators
• Mott insulator-to-metal transition in yttrium-doped CaIrO3

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