Indexed by: Journal paper

First Author: Lang Peng

Correspondence Author: Ying-Shuang Fu,Gang Xu

Co-author: 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

Journal: Physical Review Research

Included Journals: EI

Affiliation of Author(s): Huazhong University of Science and Technology

Discipline: 物理学

Document Type: J

Volume: 2

Issue: 2

Page Number: 023264

Date of Publication: 2020-06-02

Abstract: 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.