Anisotropic Dirac cones in monatomic hexagonal lattices

In the last few years, the fascinating properties of graphene have been thoroughly investigated. The existence of Dirac cones is the most important characteristic of the electronic band-structure of graphene. In this theoretical paper, hexagonal monolayers of silicon (h-Si) and germanium (h-Ge) are...

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Bibliographic Details
Published in:arXiv.org 2014-02
Main Authors: Rojas-Cuervo, A M, Fonseca-Romero, K M, Rey-González, R R
Format: Article
Language:English
Subjects:
Cones
Density functional theory
Germanium
Graphene
Lattice parameters
Lattices (mathematics)
Organic chemistry
Silicon
Online Access:Get full text
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Summary:In the last few years, the fascinating properties of graphene have been thoroughly investigated. The existence of Dirac cones is the most important characteristic of the electronic band-structure of graphene. In this theoretical paper, hexagonal monolayers of silicon (h-Si) and germanium (h-Ge) are examined using density functional theory, within the generalized gradient approximation. Our numerical results indicate that both h-Si and h-Ge are chemically stable. The lattice parameters, electronic dispersion relations and densities of states for these systems are reported. The electronic dispersion relations display Dirac cones with the symmetry of an equilateral triangle (the group D\(_3\)) in the vicinity of the K points. Hence, the Fermi velocity depends on the wave vector direction around \(K\) points. Fermi velocities for holes and electrons are significantly different. The maximum and minimum Fermi velocities are also reported.
ISSN:2331-8422
DOI:10.48550/arxiv.1304.4576