Giant Spin Splitting in Chiral Perovskites Based on Local Electrical Field Engineering
Giant Spin Splitting in Chiral Perovskites Based on Local Electrical Field Engineering
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基于局域电场工程的手性钙钛矿中的巨自旋分裂
DOI：
10.1021/acs.jpclett.1c01675
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发表时间：
2021
影响因子：
5.7
通讯作者：
Ning Zhijun
中科院分区：
文献类型：
--
作者：
Wei Qi;Zhang Qingyun;Xiang Longjun;Zhang Shihao;Liu Jianpeng;Yang Xiaoyu;Ke Youqi;Ning Zhijun
手性杂化有机-无机钙钛矿（手性 HOIP）由于其独特的自旋相关特性而呈现出潜在的自旋电子和自旋光电应用。然而，理论研究很少探讨手性 HOIP 中的自旋物理。在这里，通过第一性原理计算，我们研究了基于 Pb-I 的手性 HOIP 的自旋特性，并提出了一种有效的方法来显着增加卤素取代的手性分子的自旋分裂。与没有卤素取代的13 meV的值相比，F、Cl和Br取代的自旋分裂能可分别显着增强至73、90和105 meV。基于对称性论证的Ak·p模型哈密顿量表明，卤素取代增强了局域电场，引起PbI6八面体的畸变。进一步的计算表明，卤素取代可以强烈改变手性分子的静电势表面。这项工作提出了一种有效的分子工程方法来调节手性 HOIP 的自旋分裂，为自旋电子材料的设计提供了线索。
Chiral hybrid organic–inorganic perovskites (chiral HOIPs) present potential spintronic and spin-optoelectronic applications due to their unique spin-related properties. However, the spin physics in chiral HOIPs has rarely been explored by theoretical studies. Here, with first-principles calculations, we investigate the spin characteristics of the Pb-I based chiral HOIPs and propose an effective approach to significantly increase the spin splitting with a halogen-substituted chiral molecule. Compared to the value of 13 meV without halogen substitution, the spin splitting energy can be significantly enhanced to 73, 90, and 105 meV with F, Cl, and Br substitution, respectively. Ak·pmodel Hamiltonian based on a symmetry argument reveals that the halogen substitution enhances the local electric field, inducing distortion of the PbI6octahedron. Further calculation demonstrates that halogen substitution can strongly modify the electrostatic potential surface of the chiral molecules. This work presents an effective molecular engineering approach to modulate spin splitting of chiral HOIPs, shedding light on the design of spintronic materials.