Efficient spin-to-orbital Hall current conversion at THz frequency

Abstract

The generation of ultrafast orbital current has emerged as a subject of considerable interest in modern information technology, analogous to the role of spin currents. In this work, we demonstrate that the insertion of a thin Pt interlayer (1-3 nm) introduced between ferromagnetic and nonmagnetic layers significantly enhances the optically-driven terahertz emission. By systematically comparing nonmagnetic elements that exhibit finite spin Hall conductivity alongside relatively large orbital Hall conductivity, we establish the efficient conversion of terahertz spin currents into orbital Hall currents across nanometer-scale distances in magnetic heterostructures. © 2025 SPIE.