Electron Scattering Effect on Orbital Transport in Highly Disordered Nanocrystalline Mn

Abstract Orbital angular momentum (OAM) has emerged as an important information carrier in solids, yet how scattering influences its transport remains poorly understood. Here, we examine scattering-dependent OAM transport in single-layer, highly disordered, nanocrystalline Mn films. We quantify current-induced orbital accumulation using longitudinal magneto-optical Kerr effect measurements while systematically varying the disorder strength as gauged by their resistivity. The Kerr signal is undetectable in the least resistive films but increases sharply in more resistive films, implying that sufficiently strong disorder scattering enhances OAM transport. Thickness-dependent measurements yield orbital relaxation lengths on the order of 10 nm, far exceeding the mean free path. Moreover, the orbital accumulation exhibits an anomalous sign, which is attributed to an intrinsic boundary contribution associated with the crystal field. These results, supported by first-principles calculations, illustrate that electron scattering may even enhance orbital transport, establishing scattering control as a practical knob for boosting the orbitronic functionality.