Two-dimensional chiral perovskites with large spin Hall angle and collinear spin Hall conductivity.

Abdelwahab, Ibrahim; Kumar, Dushyant; Bian, Tieyuan; Zheng, Haining; Gao, Heng; Hu, Fanrui; McClelland, Arthur; Leng, Kai et al. · Science · 2024

basic_science · Level V

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Abstract

Two-dimensional hybrid organic-inorganic perovskites with chiral spin texture are emergent spin-optoelectronic materials. Despite the wealth of chiro-optical studies on these materials, their charge-to-spin conversion efficiency is unknown. We demonstrate highly efficient electrically driven charge-to-spin conversion in enantiopure chiral perovskites (R/S-MB)<sub>2</sub>(MA)<sub>3</sub>Pb<sub>4</sub>I<sub>13</sub> (〈<i>n</i>〉 = 4), where MB is 2-methylbutylamine, MA is methylamine, Pb is lead, and I is iodine. Using scanning photovoltage microscopy, we measured a spin Hall angle θ<sub>sh</sub> of 5% and a spin lifetime of ~75 picoseconds at room temperature in 〈<i>n</i>〉 = 4 chiral perovskites, which is much larger than its racemic counterpart as well as the lower 〈<i>n</i>〉 homologs. In addition to current-induced transverse spin current, the presence of a coexisting out-of-plane spin current confirms that both conventional and collinear spin Hall conductivities exist in these low-dimensional crystals.