Charge density waves and Fermi level pinning in monolayer and bilayer SnSe2

Materials with reduced dimensionality often exhibit exceptional properties that are different from their bulk counterparts. Here, we report the emergence of a commensurate 2×2 charge density wave (CDW) in monolayer and bilayer SnSe2 films by scanning tunneling microscopy. The visualized spatial modu...

Full description

Saved in:
Bibliographic Details
Published in:Physical review. B 2020-12, Vol.102 (24)
Main Authors: Wang, Shu-Ze, Zhang, Yi-Min, Fan, Jia-Qi, Ren, Ming-Qiang, Song, Can-Li, Ma, Xu-Cun, Xue, Qi-Kun
Format: Article
Language:English
Subjects:
Bilayers
Charge density waves
Fermi level
Fermi surfaces
Monolayers
Nesting
Phase diagrams
Pinning
Scanning tunneling microscopy
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Materials with reduced dimensionality often exhibit exceptional properties that are different from their bulk counterparts. Here, we report the emergence of a commensurate 2×2 charge density wave (CDW) in monolayer and bilayer SnSe2 films by scanning tunneling microscopy. The visualized spatial modulation of the CDW phase becomes prominent near the Fermi level, which is pinned inside the semiconductor band gap of SnSe2. We show that both CDW and Fermi level pinning are intimately correlated with band bending and virtual induced gap states at the semiconductor heterointerface. Through interface engineering, the electron-density-dependent phase diagram is established in SnSe2. Fermi surface nesting between symmetry inequivalent electron pockets is revealed to drive the CDW formation and to provide an alternative CDW mechanism that might work in other compounds.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.102.241408