单层
凝聚态物理
电荷密度波
电子结构
费米能级
密度泛函理论
材料科学
上部结构
费米能量
态密度
化学
电子
纳米技术
物理
计算化学
热力学
量子力学
超导电性
作者
Jiagui Feng,Deepnarayan Biswas,Akhil Rajan,Matthew D. Watson,Federico Mazzola,Oliver J. Clark,K. Underwood,Igor Marković,Martin McLaren,A. T. Hunter,D. M. Burn,L. B. Duffy,Sourabh Barua,G. Balakrishnan,F. Bertran,P. Le Fèvre,T. K. Kim,G. van der Laan,T. Hesjedal,Peter Wahl,P. D. C. King
出处
期刊:Nano Letters
[American Chemical Society]
日期:2018-06-18
卷期号:18 (7): 4493-4499
被引量:206
标识
DOI:10.1021/acs.nanolett.8b01649
摘要
How the interacting electronic states and phases of layered transition-metal dichalcogenides evolve when thinned to the single-layer limit is a key open question in the study of two-dimensional materials. Here, we use angle-resolved photoemission to investigate the electronic structure of monolayer VSe2 grown on bilayer graphene/SiC. While the global electronic structure is similar to that of bulk VSe2, we show that, for the monolayer, pronounced energy gaps develop over the entire Fermi surface with decreasing temperature below Tc = 140 ± 5 K, concomitant with the emergence of charge-order superstructures evident in low-energy electron diffraction. These observations point to a charge-density wave instability in the monolayer that is strongly enhanced over that of the bulk. Moreover, our measurements of both the electronic structure and of X-ray magnetic circular dichroism reveal no signatures of a ferromagnetic ordering, in contrast to the results of a recent experimental study as well as expectations from density functional theory. Our study thus points to a delicate balance that can be realized between competing interacting states and phases in monolayer transition-metal dichalcogenides.
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