Realistic flat-band model based on degenerate p-orbitals in two-dimensional ionic materials

• 作者: Jiang zeng Ming Lu Haiwen Liu Hua Jiang X.C.Xie
• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2021,（8）
• 所属期刊栏目: ARTICLES
• 页码范围: 765-770
• 页数: 6页
• 语种: 英文

摘要

Though several theoretical models have been proposed to design electronic flat-bands,the definite exper imental realization in two-dimensional atomic crystal is still lacking.Here we propose a novel and realistic flat-band model based on threefold degenerate p-orbitals in two-dimensional ionic materials.Our theoretical analysis and first-principles calculations show that the proposed flat-band can be realized in 1T layered materials of alkali-metal chalogenides and metal-carbon group compounds.Some of the former are theoretically predicted to be stable as layered materials (e.g.,K2S),and some of the latter have been experimentally fabricated in previous works (e.g.,Gd2CCl2).More interestingly,the flat-band is partially filled in the heterostructure ofa K2S monolayer and graphene layers.The spin polarized nearly flatband can be realized in the ferromagnetic state of a Gd2CCl2 monolayer,which has been fabricated in experiments.Our theoretical model together with the material predictions provide a realistic platform for the study of flat-bands and related exotic quantum phases.