近日，新加坡国立大学的Kian Ping Loh&Hyunsoo Yang及其研究小组与香港理工大学的殷骏等人合作并取得一项新进展。经过不懈努力，他们成功研制出具有大自旋霍尔角和共线自旋霍尔电导率的二维手性钙钛矿。相关研究成果已于2024年7月19日在国际权威学术期刊《科学》上发表。

该研究团队在探究具有对映纯手性的钙钛矿材料(R/S-MB)₂(MA)₃Pb₄I₁₃（其中MB代表2-甲基丁胺，MA为甲胺，Pb为铅，I为碘，n=4）时，成功验证了其高效的电驱动电荷-自旋转换能力。

研究人员利用扫描光电压显微镜，测量了n = 4的手性钙钛矿在室温下的自旋霍尔角θ_sh为5%，自旋寿命约为75皮秒，远大于其外消旋对应物以及低n同源物。除了电流诱导的横向自旋电流外，共存的面外自旋电流的存在证实了这些低维晶体中存在常规和共线自旋霍尔电导率。

据悉，具有手性自旋织构的二维杂化有机-无机钙钛矿是新兴的自旋光电材料。尽管对这些材料进行了丰富的手性光学研究，但它们的电荷-自旋转换效率尚不清楚。

附：英文原文

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

Author: 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

Issue&Volume: 2024-07-19

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)₃Pb₄I₁₃ (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 θsh 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.

DOI: 10.1126/science.adq0967

Source: https://www.science.org/doi/10.1126/science.adq0967