Highly Efficient Spin‐Filtering Transport in Chiral Hybrid Copper Halides

Abstract Chiral Pb(Sn)‐I hybrid organic–inorganic perovskites exhibit outstanding chiral‐induced spin selectivity (CISS) performance, but the nontoxic lead‐free hybrid materials with high stability are still greatly desired for spin filtering in spintronic applications. We synthesize chiral hybrid copper halides ( R / S ‐MBA) 2 Cu X 4 (MBA=methylbenzylammonium; X= Cl, Br) with characteristic 0D Cu X 4 tetrahedral structural motifs, combining the low toxicity of Cu 2+ and air stability of halide ions (Cl − and Br − ). Despite similar structural and electronic features, ( R / S ‐MBA) 2 CuBr 4 shows much smaller chiroptical activity than the chloride counterpart. Magnetically conductive atomic force microscopy measurements display a typical spin‐polarized charge‐transport property with high efficiency up to 90 % for both copper halides. Our work expands the CISS effect into eco‐friendly and stable metal–organic halides, which is promising for applications in spintronics based on transition‐metal hybrid systems.