Electron transport in the topological metal Molybdenum Phosphide

With aggressive down-scaling of integrated circuits and the concomitant reduction of the dimensions of the interconnect lines, the search for a new interconnect material to replace the ubiquitously used Cu has become more important than ever. When the electron mean free path, λ becomes equal to or less than the dimensions of the interconnect lines, there is a dramatic increase in the resistivity, ρ which adversely impacts the efficiency and performance of the circuits. Hence, there is an ongoing search for metals that could supplant copper as the narrow interconnect metal. While conventional metals like cobalt, ruthenium and iridium are being considered as substitutes, there has been an increased interest in other non-elemental metals (like intermetallics and MAX phases) and topological metals (like MoP). In this work, we use first-principles calculations to evaluate the performance and prospect of a topological semi-metal MoP as a future interconnect material. We perform Landauer conductance calculations for different orientations and film thicknesses. The change in conductance with the introduction of surface vacancies and defects throw light on the topological protection offered to electron transport by MoP.