Circular photogalvanic effect in Cu/Bi bilayers

Abstract

We have studied the circular photogalvanic effect (CPGE) in Cu/Bi bilayers. When a circularly polarized light in the visible range is irradiated to the bilayer from an oblique incidence, we find a photocurrent that depends on the helicity of light. Such photocurrent appears in a direction perpendicular to the light plane of incidence but is absent in the parallel configuration. The helicity dependent photocurrent is significantly reduced for a Bi single layer film and the effect is nearly absent for a Cu single layer film. Conventional interpretation of the CPGE suggests the existence of spin-momentum locked band(s) of a Rashba type in the Cu/Bi bilayer. In contrast to previous reports on the CPGE studied in other systems, however, the light energy used here to excite the carriers is much larger than the band gap of Bi. Moreover, the CPGE of the Cu/Bi bilayer is larger when the energy of the light is larger: the helicity dependent photocurrent excited with a blue light is nearly two times larger than that of a red light. We therefore consider the CPGE of the Cu/Bi bilayer may have a different origin compared to conventional systems.

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Cited by in corpus (5)

• Photoinduced Rashba spin to charge conversion via interfacial unoccupied state
• Interface enhanced helicity dependent photocurrent in metal/semimetal bilayers
• Giant inverse Faraday effect in Dirac semimetals
• Evidence for spin swapping from modulation of transverse resistance in magnetic heterostructures with Rashba interface
• Surface Circular Photogalvanic Effect in Tl-Pb Monolayer Alloys on Si(111) with Giant Rashba Splitting