Lead-Free Hybrid Perovskite: An Efficient Room-Temperature Spin Generator via Large Interfacial Rashba Effect

Two-dimensional (2D) hybrid organic-inorganic perovskite (HOIP) shows great potential for developing flexible and wearable spintronic devices by serving as spin sources via the bulk Rashba effect (BRE). However, the practical application of BRE in 2D HOIP faces huge challenges, particularly due to the toxicity of lead, which is crucial for achieving large spin-orbit coupling, and the restrictions in 2D HOIP candidates to meet specific symmetry-breaking requirements. To overcome these obstacles, we designed a strategy to exploit the interfacial Rashba effect (IRE) of lead-free 2D HOIP (C₆H₅CH₂CH₂NH₃)₂CuCl₄ (PEA-CuCl), manifesting as an efficient spin generator at room temperature. IRE of PEA-CuCl originates from the large orbital hybridization at the interface between PEA-CuCl and adjacent ferromagnetic layers. Spin-torque ferromagnetic resonance measurements further quantify a large Rashba effective field of 14.04 Oe per 10¹¹ A m^-2, surpassing those of lead-based HOIP and traditional all-inorganic heterojunctions with noble metals. Our lead-free 2D HOIP PEA-CuCl, which harnesses large IRE for spin generation, is efficient, nontoxic, and economic, offering huge promise for future flexible and wearable spintronic devices.