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arXiv · 2610.30547

Anisotropic thermoelectric transport in the Sr2RuO4-Ru eutectic system

Takeru Ito·Shogo Yoshida·Hiroshi Yaguchi·Ryuji Okazaki
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Abstract

The Sr2RuO4-Ru eutectic system, in which metallic Ru inclusions are embedded in a Sr2RuO4 matrix, exhibits an enhanced superconducting onset temperature of about 3 K, known as the 3-K phase. Here we investigate the in-plane thermoelectric response of this eutectic system in the normal state and find a pronounced anisotropy in the thermopower for thermal gradients applied parallel and perpendicular to the Ru lamellae. To clarify its origin, we combine thermopower measurements with electronic-structure-based transport calculations and finite-element modeling of the local strain distribution generated by the thermal-expansion mismatch between Sr2RuO4 and Ru. The calculations show that uniaxial compression of Sr2RuO4 produces a sizable thermopower anisotropy through modification of the Fermi surfaces. When an idealized spatially inhomogeneous strain field around the Ru lamellae is included, the observed sign and qualitative magnitude of the anisotropy are reproduced more closely than in a simple unstrained two-component model. These results are consistent with a substantial contribution from strain-induced changes in the Sr2RuO4 electronic structure near the interfaces, although contributions from interfacial phase mixing and three-dimensional transport connectivity cannot be excluded.

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Takeru Ito, Shogo Yoshida, Hiroshi Yaguchi, Ryuji Okazaki. 2026-10-22. Anisotropic thermoelectric transport in the Sr2RuO4-Ru eutectic system. https://arxiv.org/abs/2610.30547

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