Two-dimensional chiral perovskites with large spin Hall angle and collinear spin Hall conductivity
Ibrahim Abdelwahab, Dushyant Kumar, Tieyuan Bian, Haining Zheng, Heng Gao, Fanrui Hu, Arthur McClelland, Kai Leng, William L. Wilson, Jun Yin, Hyunsoo Yang, Kian Ping Loh
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) 2 (MA) 3 Pb 4 I 13 (〈 n 〉 = 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 sh of 5% and a spin lifetime of ~75 picoseconds at room temperature in 〈 n 〉 = 4 chiral perovskites, which is much larger than its racemic counterpart as well as the lower 〈 n 〉 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.