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Magic of high-order van Hove singularity.

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.

SUBMITTER: Yuan NFQ

PROVIDER: S-EPMC6920381 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature

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Magic of high-order van Hove singularity.

Yuan Noah F Q NFQ Isobe Hiroki H Fu Liang L

Nature communications 20191218 1

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 graphen ...[more]

PMID: 31852901

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