Chirality Versus Symmetry: Electron's Spin Selectivity in Non‐Polar Chiral Lead‐Bromide Perovskites
Résumé
In the last decade, chirality-induced spin selectivity (CISS), the spin-selective electron transport through chiral molecules, has been described in a large range of materials, from insulators to superconductors. Because more experimental studies are desired for the theoretical understanding of the CISS effect, chiral metal-halide semiconductors may contribute to the field thanks to their chiroptical and spintronic properties. In this regard, we use new chiral organic cations S-HP1A and R-HP1A (HP1A= 2-hydroxy-propyl-1-ammonium) to prepare two-dimensional (2D) chiral halide perovskites (HPs) which crystallize in the enantiomorphic space groups P43212 and P41212, respectively. The four-fold symmetry induces antiferroelectricity along the stacking axis which, combined to incomplete Rashba-like splitting in each individual 2D polar layer, results in rare spin textures in the band structure. As revealed by magnetic conductive-probe AFM measurements, these materials show CISS effect with partial spin polarization (±40-45%). This incomplete effect is efficient enough to drive a chiro-spintronic device as demonstrated by the fabrication of spin valve devices with magnetoresistance responses up to 250 K. Therefore, these stable lead-bromide HP materials not only represent interesting candidates for spintronic applications but also reveal the importance of polar symmetry-breaking topology for spin selectivity
Domaines
MatériauxOrigine | Publication financée par une institution |
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