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TT: Fachverband Tiefe Temperaturen

TT 67: Unconventional Superconductors

TT 67.5: Talk

Thursday, March 21, 2024, 10:45–11:00, H 3007

Non-local electronic correlations and spin excitations in Sr₂RuO₄ — •Maria Chatzieleftheriou¹, Silke Biermann^1,2,3, Yvan Sidis⁴, and Evgeny Stepanov^1,2 — ¹Ecole Polytechnique, Palaiseau, France — ²Collège de France, Paris, France — ³ETSF, Palaiseau, France — ⁴CEA/CNRS, Gif-sur-Yvette, France

In this work we study the effect of non-local correlations on the electronic properties of Sr₂RuO₄. We go beyond the state-of-the-art single-site description of Dynamical Mean-Field Theory (DMFT) [1] by deploying the D-TRILEX [2-4] self-consistent diagrammatic expansion method. We calculate the magnetic susceptibility and find that accounting for spatial fluctuations indeed leads to a very good agreement with the experimental evidence. In particular, we find an accurate description of the static spin susceptibility and observe a dome-like structure centred around the Γ point, in agreement with the experimental evidence and in contrast to previous theoretical studies. Moreover, we observe the quasi-ferromagnetic fluctuations reported in the experimental work [5] upon increasing the Hund’s exchange coupling.

[1] A. Georges et al., Rev. Mod. Phys. 68 (1996) 13

[2] E. A. Stepanov et al., Phys. Rev. B 100 (2019) 205115

[3] V. Harkov et al., Phys. Rev. B 103 (2021) 245123

[4] M. Vandelli et al., SciPost Phys. 13, 0366

[5] P. Steffens et al. Phys. Rev. Lett. 122 (2022) 047004 (2019)

Keywords: Ruthenates; electronic correlations; magnetic fluctuations; spin excitations