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TT: Fachverband Tiefe Temperaturen

TT 7: Correlated Electrons: Electronic Structure Calculations

TT 7.4: Vortrag

Montag, 17. März 2025, 15:45–16:00, H31

Origin of transitions inversion in rare-earth vanadates — •Xuejing Zhang1, Erik Koch2, and Eva Pavarini11Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany — 2Jülich Supercomputing Centre, Forschungszentrum Jülich, 52425 Jülich, Germany

The surprising inversion of the orbital- and magnetic-order transitions in the RVO3 series with increasing the rare-earth radius makes the series unique among orbitally-ordered materials [1]. Here, augmenting dynamical mean-field theory with order-parameter irreducible-tensor decomposition [2], we show that this anomalous behavior emerges from an unusual hierarchy of interactions. First, increasing the rare-earth radius, orbital physics comes to be controlled by xz-xz quadrupolar super-exchange rather than by lattice distortion. Next, for antiferromagnetic spin order, orbital super-exchange terms with different spin rank compete, so that the dipolar spin-spin interaction dominates. Eventually, G-type magnetic order (anti-ferro in all directions) can appear already above the orbital ordering transition and C-type order (anti-ferro in the ab plane) right around it. The strict constraints we found also explain why the inversion is rare, and give at the same time criteria to look for similar behavior in other materials [3].

[1] S. Miyasaka, Y. Okimoto, M. Iwama, Y. Tokura, Phys. Rev. B 68, 100406(R) (2003).

[2] X.J.Zhang, E.Koch, E.Pavarini, Phys.Rev.B 105, 115104 (2022).

[3] X. J. Zhang, E. Koch, E. Pavarini, arXiv:2411.16351 (2024).

Keywords: Orbital- and magnetic-order transitions; RVO3; LDA+DMFT; Super-exchange coupling; Electron-lattice interaction

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