Photoinduced Rashba spin to charge conversion via interfacial unoccupied state

Abstract

At interfaces with inversion symmetry breaking, Rashba effect couples the motion of electrons to their spin; as a result, spin-charge interconversion mechanism can occur. These interconversion mechanisms commonly exploit Rashba spin splitting at the Fermi level by spin pumping or spin torque ferromagnetic resonance. Here, we report evidence of significant photoinduced spin to charge conversion via Rashba spin splitting in an unoccupied state above the Fermi level at the Cu(111)/$\alpha$-Bi${}_2$O${}_3$ interface. We predict an average Rashba coefficient of $1.72\times 10^{-10}eV.m$ at 1.98 eV above the Fermi level, by fully relativistic first-principles analysis of the interfacial electronic structure with spin orbit interaction. We find agreement with our observation of helicity dependent photoinduced spin to charge conversion excited at 1.96 eV at room temperature, with spin current generation of $J_s=10^{6}A/m^2$. The present letter shows evidence of efficient spin-charge conversion exploiting Rashba spin splitting at excited states, harvesting light energy without magnetic materials or external magnetic fields.

arXiv comment7 pages, 4 figures in main text and 5 figures in appendix

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• Interface enhanced helicity dependent photocurrent in metal/semimetal bilayers
• Magnetization generated by microwave-induced Rashba interaction
• Giant inverse Faraday effect in Dirac semimetals
• Evidence for spin swapping from modulation of transverse resistance in magnetic heterostructures with Rashba interface
• Two-dimensional electron gas in a metal/amorphous oxide interface with spin orbit interaction
• Scaling law for the Rashba-type spin splitting in quantum well films
• Surface Circular Photogalvanic Effect in Tl-Pb Monolayer Alloys on Si(111) with Giant Rashba Splitting