论文类型：期刊论文
第一作者：Lang Peng
通讯作者：Ying-Shuang Fu,Gang Xu
合写作者：Tao Xiang,Zeng-Wei Zhu,Ling-Xiao Zhao,Wen-Hao Zhang,Yuan Yuan,Hui-Nan Xia,Zhen-Yu Liu,Gui-Yuan Hua,Min Cai,Jianzhou Zhao
发表刊物：Physical Review Research
收录刊物：EI
所属单位：华中科技大学
学科门类：物理学
文献类型：J
卷号：2
期号：2
页面范围：023264
发表时间：2020-06-02
摘要：Two-dimensional materials offer opportunities for unravelling unprecedented ordered states at the single-layer limit. Among such ordered states, the Mott phase is rarely explored. Here we study the Mott phase in van der Waals chromium (II) iodide (CrI2) films. High-quality CrI2 films with an atomically flat surface and macro size are grown on graphitized 6H-SiC(0001) substrate by molecular beam epitaxy. By in situ low-temperature scanning tunneling microscopy and spectroscopy, we reveal that the film has a band gap as large as ∼3.2eV, which is nearly thickness independent. Density functional plus dynamic mean-field theory calculations suggest that CrI2 films may be a strong Mott insulator with a ferromagnetically ordered ground state. The Mott phase is corroborated by the spectral band splitting and spectral weight transfer at charge dopants that is consistent with the extended Hubbard model. Our study provides a platform for studying correlated electron states at the single-layer limit.