Magic of high-order van Hove singularity

Journal Article · 17 December 2019 · Nature Communications

DOI: https://doi.org/10.1038/s41467-019-13670-9 · OSTI ID:1619726

Yuan, Noah F. Q. ; Isobe, Hiroki; Fu, Liang

Abstract The van Hove singularity in density of states generally exists in periodic systems due to the presence of saddle points of energy dispersion in momentum space. We introduce a new type of van Hove singularity in two dimensions, resulting from high-order saddle points and exhibiting power-law divergent density of states. We show that high-order van Hove singularity can be generally achieved by tuning the band structure with a single parameter in moiré superlattices, such as twisted bilayer graphene by tuning twist angle or applying pressure, and trilayer graphene by applying vertical electric field. Correlation effects from high-order van Hove singularity near Fermi level are also discussed.

• Research Organization: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC)
• Grant/Contract Number: SC0018945
• OSTI ID: 1619726
• Journal Information: Nature Communications, Journal Name: Nature Communications Journal Issue: 1 Vol. 10; ISSN 2041-1723
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: United Kingdom
• Language: English