Oxygen-vacancy-mediated efficient charge-to-spin conversion

Abstract This study proposes oxygen vacancy engineering as an effective strategy to achieve efficient charge-to-spin conversion in heavy-metal oxides, establishing a novel theoretical framework for semiconductor spintronics devices. Using first-principles calculations, we systematically investigate the impact of oxygen vacancy on the intrinsic spin Hall conductivity (ISHC) and spin Hall angle (SHA) of room-temperature-stable monoclinic WO 3 . Incorporating oxygen vacancies raises the Fermi level into the conduction band, significantly enhancing ISHC from zero to near 10 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi/> <mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> magnitude. At low vacancy concentrations, WO 3 achieves exceptional charge-to-spin conversion efficiency (i.e. SHA) up to 72.6%, whereas elevated concentrations induce disproportionate enhancement in charge conductivity relative to ISHC gains, consequently reducing SHA. The cubic-like structure of WO 3 ensures that oxygen vacancy positions exert negligible influence on ISHC magnitude. These findings establish WO 3 as a promising spintronics material, demonstrating the dual functionality of oxygen vacancies as enhancers of both charge conductivity and spin current. The synergistic integration of defect engineering with heavy-metal oxides opens new pathways for spintronics device applications.