Size-Dependent Grain Boundary Scattering in Topological Semimetals

Abstract

We assess the viability of topological semimetals for application in advanced interconnect technology, where conductor size is on the order of a few nanometers and grain boundaries are expected to be prevalent. We investigate the electron transport properties and grain boundary scattering in thin films of the topological semimetals CoSi and CoGe using first-principles calculations combined with the Non-Equilibrium Green's Function (NEGF) technique. Unlike conventional interconnect metals like Cu and Al, we find that CoSi and CoGe conduct primarily through topologically-protected surface states in thin film structures even in the presence of grain boundaries. The area-normalized resistance decreases with decreasing film thickness for CoSi and CoGe thin films both with and without grain boundaries; a trend opposite to that of the conventional metals Cu and Al. The surface-dominated transport mechanisms in thin films of topological semimetals with grain boundaries demonstrates a fundamentally new paradigm of the classical resistivity size-effect, and suggests that these materials may be promising candidates for applications as nano-interconnects where high electrical resistivity acts as a major bottleneck limiting semiconductor device performance.

18 pages, 9 figures. To be published in Physical Review Applied

References in corpus (7)

• Multiple types of topological fermions in transition metal silicides
• Large Fermi Arcs in Unconventional Weyl Semimetal RhSi
• Discovery of topological chiral crystals with helicoid arc states
• New classes of chiral topological nodes with non-contractible surface Fermi arcs in CoSi
• Weyl Semimetals, Fermi Arcs and Chiral Anomalies (A Short Review)
• Electron transport properties of sub-3-nm diameter copper nanowires
• Strain-induced topological charge control in multifold fermion systems

Cited by in corpus (5)

• Surface-dominated conductance scaling in Weyl semimetal NbAs
• Magnetic Breakdown and Chiral Magnetic Effect at Weyl-Semimetal Tunnel Junctions
• Nonlinear longitudinal current of band-geometric origin in wires of finite thickness
• Tunnelling theory of Weyl semimetals in proximity to a metallic band
• Surface states and finite size effects in triple-fold semimetals