Resistivity scaling in topological semimetal CoSi

Topological Weyl physics associated with anomalous transport properties provides a potential solution to the resistance bottleneck in metal-interconnect scaling. The Fermi-arc surface states in topological semimetals can contribute substantially to conductivity even when the system size is large. We use the chiral topological semimetal CoSi as a model system to demonstrate the decreasing resistivity with scaling. Wannier-function-based tight-binding models derived from first-principles calculations are used to calculate both the surface and bulk scattering rates due to the vacancies. Thickness dependence of resistivity in (001) CoSi slabs is investigated theoretically via a semiclassical approach. For sufficiently thin slabs, the surface current dominates. As a result, the film resistivity decreases with decreasing thickness even in the presence of defects, in sharp contrast to the resistivity scaling in conventional metals. Our study shows the promise of considering topological semimetals as candidate materials for the beyond-Cu scaled interconnects.