$\mathrm{LaR}{\mathrm{u}}_3\mathrm{S}{\mathrm{i}}_2$ is a kagome superconductor with a relatively high superconducting transition temperature of $T_{\mathrm{c}}\approx 7.0\mathrm{K}$, making it a promising candidate for exploring the relationship between superconductivity and exotic electronic properties in a kagome lattice. We report on the superconducting properties of $\mathrm{LaR}{\mathrm{u}}_3\mathrm{S}{\mathrm{i}}_2$ through electrical resistivity, heat-capacity, and point-contact spectroscopy measurements. The temperature dependence of the upper critical field and low-temperature electronic specific heat is best described by single $s$-wave superconductivity. This conclusion is further supported by point-contact spectroscopy results, which, when analyzed by the modified Blonder-Tinkham-Klapwijk model, are consistent with the $s$-wave superconducting gap Δ. The evolution of Δ as a function of temperature and magnetic field follows the behavior characteristic of conventional Bardeen-Cooper-Schrieffer (BCS) superconductors, with a zero-temperature value $\mathrm{\Delta }\left(0\right)$ of 1.2 meV. The gap-to-$T_{\mathrm{c}}$ ratio $2\mathrm{\Delta }\left(0\right)/k_{\mathrm{B}}{T}_{\mathrm{c}}$ is 4.27, which is larger than the weak-coupling BCS value of 3.52, indicating that $\mathrm{LaR}{\mathrm{u}}_3\mathrm{S}{\mathrm{i}}_2$ belongs to the family of moderately coupled superconductors. These results can guide future research in understanding the enhancement of $T_{\mathrm{c}}$ and the underlying pairing mechanism in the geometrically frustrated systems.

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• Andreev reflection
• Pairing mechanisms
• Superconducting gap
• Kagome lattice
• Andreev point contact spectroscopy