Nontrivial band topologies in semimetals lead to robust surface states that can contribute dominantly to the total conduction. This may result in reduced resistivity with decreasing feature size contrary to conventional metals, which may highly impact the semiconductor industry. Here we study the resistivity scaling of a representative topological semimetal CoSi using realistic band structures and Green’s function methods. We show that there exists a critical thickness d_c dividing different scaling trends. Above d_c, when the defect density is low such that surface conduction dominates, resistivity reduces with decreasing thickness; when the defect density is high such that bulk conduction dominates, resistivity increases as in conventional metals. Below d_c where bulk states are depopulated, the persistent Fermi-arc remnant states give rise to decreasing resistivity down to the ultrathin limit, unlike topological insulators. The observed CoSi scaling can apply to broad classes of topological semimetals, providing guidelines for materials screening in back-end-of-line interconnect applications.

半金属中的非平凡能带拓扑导致稳健的表面状态，这对总传导起着主导作用。与传统金属相反，这可能会导致电阻率随着特征尺寸的减小而降低，这可能会对半导体行业产生重大影响。在这里，我们使用真实的能带结构和格林函数方法研究了具有代表性的拓扑半金属 CoSi 的电阻率缩放。我们表明存在一个临界厚度d _c划分不同的缩放趋势。在dc以上，当缺陷密度低以致于表面传导占主导地位时，电阻率随着厚度的减小而降低_；当缺陷密度很高以至于体积传导占主导地位时，电阻率会像传统金属一样增加。以下与拓扑_绝缘体不同，在体积状态减少的情况下，持久的费米弧残余状态会导致电阻率降低到超薄极限。观察到的 CoSi 缩放可应用于广泛类别的拓扑半金属，为后端线互连应用中的材料筛选提供指导。