标题： Kagome晶格超导体LaRh$_3$B$_2$中各项异性序参量的光谱特征 显示英文标题

标题： Spectroscopic signature of anisotropic order parameter in Kagome lattice superconductor LaRh$_3$B$_2$

摘要： Kagome金属LaRh$_3$B$_2$的物理性质以及其在2.6 K以下的超导性与其他流行的Kagome金属不同，据知不受电子关联的显著影响。虽然用于探测LaRh$_3$B$_2$整体超导特性的间接技术表明具有常规各向同性的序参量，但我们展示了通过直接光谱确定超导能隙的方法揭示了LaRh$_3$B$_2$和正常金属之间Andreev反射的异常抑制。这一观察提示可能存在不完全的超导能隙形成，至少在某些动量方向上，并伴随低能准粒子态的存在。 分析在 LaRh$_3$B$_2$表面不同位置捕获的多个安德烈夫反射光谱，揭示了超导能隙的分布情况，与各项异性超导序参量一致。 显示英文摘要

摘要： The physics of the Kagome metal LaRh$_3$B$_2$ along with its superconductivity below 2.6 K, unlike other popular Kagome metals, is not known to be significantly influenced by the electron correlations. While the indirect techniques to probe the bulk superconducting properties of LaRh$_3$B$_2$ indicate a conventional isotropic order parameter, we show that the direct spectroscopic determination of the superconducting energy gap reveals an anomalous suppression of Andreev reflection between LaRh$_3$B$_2$ and a normal metal. This observation hints to the presence of incomplete superconducting gap formation, at least along certain momentum directions, and consequent low-lying quasiparticle states. An analysis of multiple Andreev reflection spectra captured at different points on the surface of LaRh$_3$B$_2$ reveals a distribution of the superconducting energy gap which is consistent with an anisotropic superconducting order parameter.