Enhanced Valley Splitting of Transition-Metal Dichalcogenide by Vacancies in Robust Ferromagnetic Insulating Chromium Trihalides
Enhanced Valley Splitting of Transition-Metal Dichalcogenide by Vacancies in Robust Ferromagnetic Insulating Chromium Trihalides
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鲁棒铁磁绝缘三卤化铬中的空位增强了过渡金属二硫属化物的谷分裂
DOI：
10.1021/acsami.9b04843
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发表时间：
2019-05-22
影响因子：
9.5
通讯作者：
Huang, Wei
中科院分区：
文献类型：
--
作者：
Lin, Changqing;Li, Yiran;Huang, Wei
最近，三卤化铬CrX3中的单层CrI3被剥离，并被实验证明是一种适合于二维自旋电子学的原子薄材料。在WSe_2/CrI_3范德华异质结中，由于磁邻近效应而产生的谷分裂已被证明。然而，对CrI3良好性能背后的机制的了解仍然有限。在这里，我们系统地研究了CrX3中的载流子迁移率和本征点缺陷，并用第一性原理计算评估了它们对WSe2/CrI3中谷分裂的影响。平带特性导致了极大的载流子质量和极低的载流子迁移率。此外，本征点缺陷-禁带中部的局域态-显示出较深的跃迁能级，并作为载流子复合中心，进一步降低了载流子迁移率。此外，CrI3中的空位可以增强WSe2/CrI3异质结的铁磁性和谷分裂，证明了三卤化铬是一种优良的自旋电子和电子电子铁磁绝缘体。
Recently, single-layer CrI3, a member of the chromium trihalides CrX3 (where X = Cl, Br, or I), has been exfoliated and experimentally demonstrated as an atomically thin material suitable for two-dimensional spintronics. Valley splitting due to the magnetic proximity effect has been demonstrated in a WSe2/CrI3 van der Waals heterojunction. However, the understanding of the mechanisms behind the favorable performance of CrI3 is still limited. Here, we systematically study the carrier mobility and the intrinsic point defects in CrX3 and assess their influence on valley splitting in WSe2/CrI3 by first-principles calculations. The flat-band nature induces extremely large carrier mass and ultralow carrier mobility. In addition, intrinsic point defects-localized states in the middle of the band gap-show deep transition energy levels and act as carrier recombination centers, further lowering the carrier mobility. Moreover, vacancies in CrI3 can enhance ferromagnetism and valley splitting in a WSe2/CrI3 heterojunction, proving that chromium trihalides are excellent ferromagnetic insulators for spintronic and valleytronic applications.