Surface-enhanced spin current to charge current conversion efficiency in CH₃NH₃PbBr₃-based devices.

Area of Science:

• Spintronics
• Materials Science
• Condensed Matter Physics

Background:

• Hybrid organic-inorganic perovskites exhibit strong spin-orbit coupling due to heavy elements like lead.
• Surface-induced Rashba splitting in CH3NH3PbBr3 suggests potential for efficient spin-current-to-charge-current (StC) conversion.

Purpose of the Study:

• To experimentally demonstrate and quantify the StC conversion efficiency in ferromagnet/CH3NH3PbBr3 heterostructures.
• To investigate the underlying mechanism of StC conversion, particularly the role of the perovskite surface.

Main Methods:

• Utilized pulsed spin-pumping technique to generate spin currents.
• Measured spin-to-charge conversion via the inverse spin Hall effect in ferromagnet/CH3NH3PbBr3 devices.
• Employed a LiF insertion layer to probe the surface contribution to StC conversion.

Main Results:

• Observed an anomalous increase in StC conversion efficiency with decreasing perovskite layer thickness.
• Demonstrated that the StC conversion is surface-dominated, consistent with the inverse Rashba-Edelstein effect.
• Significantly suppressed StC conversion by inserting a LiF layer, confirming the presence of a Rashba surface effect.

Conclusions:

• The study provides the first experimental demonstration of efficient spin-current-to-charge-current conversion in hybrid perovskites.
• The findings highlight the critical role of the perovskite surface and the inverse Rashba-Edelstein effect in spin-charge conversion.
• These results pave the way for developing novel spintronic devices based on hybrid perovskites.