Exploring Topological Semimetals for Highly Scaled Interconnects Beyond Copper

Due to surface and disorder scattering, resistivity of metal wires keeps increasing with shrinking dimensions, which severely impacts the performance of highly scaled integrated circuits. Here we explore a new class of materials – topological semimetals – as an alternative solution. We demonstrate that, via conduction of the protected surface electronic states, resistivity in topological semimetals reduces with decreasing feature size down to ~ nm scale, even in the presence of defects and grain-boundary scattering. This novel scaling behavior sharply contrasts that of conventional metals, such as Cu, and topological insulators. In this talk, we will first present first-principles-based electrical transport calculations of a Si-CMOS compatible topological semimetal CoSi and a prototypical Weyl semimetal NbAs. We will then report experimental evidence for surface-dominated transport in CoSi thin films, showing resistivity below that of the bulk single-crystals. Our proof-of-principle study demonstrates the potential of topological semimetal as beyond Cu interconnect materials.