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arXiv · 2507.04693

Tuning electronic correlations in the Kagome metals $RT_3$B$_2$

Savita Chaudhary·Armando Consiglio·Jaskaran Singh·Domenico Di Sante·Ronny Thomale·Yogesh Singh
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Abstract

The $RT_3$B$_2$ ($R=$Y, Lu, $T=$ Co, Os) family hosts a perfect kagome lattice of $T$ atoms, offering an interesting platform to investigate the interplay of electronic structure, superconductivity, and lattice dynamics. Here, we compare two members of this family, LuOs$_3$B$_2$ and YCo$_3$B$_2$, with similar crystallography but differing chemical composition, leading to distinct electronic correlation strengths and spin-orbit coupling effects. We confirm superconductivity in LuOs$_3$B$_2$ with $T_c = 4.75$K, while YCo$_3$B$_2$ remains non-superconducting above 1.8K. First-principles estimates of the electron-phonon coupling for LuOs$_3$B$_2$ are consistent with its observed $T_c$ and suggest a moderate coupling strength. Both materials exhibit kagome-derived electronic features, including quasi-flat bands, Dirac cones, and van Hove singularities. Fermi surface calculations reveal quasi-one-dimensional behavior along the $c$-axis in YCo$_3$B$_2$, in contrast to the more three-dimensional Fermiology of LuOs$_3$B$_2$. Phonon calculations for LuOs$_3$B$_2$ show imaginary modes, indicating potential lattice instabilities. Experimental estimates of the Wilson and Kadowaki-Woods ratios point to non-negligible electronic correlations in both compounds.

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Savita Chaudhary, Armando Consiglio, Jaskaran Singh, Domenico Di Sante, Ronny Thomale, Yogesh Singh. 2025-07-07. Tuning electronic correlations in the Kagome metals $RT_3$B$_2$. https://arxiv.org/abs/2507.04693

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