164 research outputs found
Natural charge spatial separation and quantum confinement of ZnO/GaN core/shell nanowires
We performed density-functional calculations to investigate the electronic
structure of ZnO/GaN core/shell heterostructured nanowires (NWs) orientating
along direction. The build-in electric filed arising from the charge
redistribution at the {1-100} interfaces and the band offsets were revealed.
ZnO-core/GaN-shell NWs rather than GaN-core/ZnO-shell ones were predicted to
exhibit natural charge spatial separation behaviors, which are understandable
in terms of an effective mass model. The effects of quantum confinement on the
band gaps and band offsets were also discussed.Comment: 3 pages, 3 figure
Phagraphene: A Low-energy Graphene Allotrope composed of 5-6-7 Carbon Rings with Distorted Dirac Cones
Using systematic evolutionary structure searching we propose a new carbon
allotrope, phagraphene, standing for penta-hexa-hepta-graphene, because the
structure is composed of 5-6-7 carbon rings. This two-dimensional (2D) carbon
structure is lower in energy than most of the predicted 2D carbon allotropes
due to its sp2-hybridization and density of atomic packing comparable to
graphene. More interestingly, the electronic structure of phagraphene has
distorted Dirac cones. The direction-dependent cones are further proved to be
robust against external strain with tunable Fermi velocities.Comment: 5 pages, 3 figure
- …