Related Experiment Video
Updated: Apr 2, 2026
11:42
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
16.3K
Finite-size effects and interactions in artificial graphene formed by repulsive scatterers
I Kylänpää1, M Aichinger, S Janecek
1Department of Physics, Tampere University of Technology, FI-33101 Tampere, Finland.
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|September 30, 2015
Summary
This study models molecular graphene, showing how a Dirac point emerges in electron density of states as system size increases. Electron-electron interactions play a minor role, requiring strong scattering for a distinct Dirac point.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Computational Physics
Background:
- Electrons confined in 2D triangular lattices model molecular graphene.
- Hexagonal configuration of scattering centers influences electron gas behavior.
- Understanding finite vs. periodic systems is crucial for material properties.
Purpose of the Study:
- Compare finite (flake) and periodic systems for electrons in a triangular lattice.
- Investigate the role of Coulombic electron-electron interactions.
- Determine the influence of scattering center strength on electronic properties.
Main Methods:
- Numerical real-space study of confined electrons.
- Analysis of electron density of states formation.
- Comparison with experimental data for qualitative agreement.
Main Results:
- Density of states in periodic systems, including the Dirac point, forms gradually with increasing flake size.
- Electron-electron interactions have a minor role for the chosen system parameters.
- Significant scattering amplitudes are necessary to observe a distinct Dirac point.
Conclusions:
- Finite system size influences the emergence of the Dirac point in molecular graphene models.
- Scattering strength is a critical factor in observing key electronic features.
- The model provides qualitative agreement with experimental density of states data.
Related Concept Videos
01:24Van der Waals Interactions
73.2K
Atoms and molecules interact with each other through intermolecular forces. These electrostatic forces arise from attractive or repulsive interactions between particles with permanent, partial, or temporary charges. The intermolecular forces between neutral atoms and molecules are ion–dipole, dipole–dipole, and dispersion forces, collectively known as van der Waals forces.
73.2K
01:24Comparison Between Electrical And Gravitational Forces
4.4K
There are four fundamental forces in nature: the gravitational force, the electromagnetic force, the strong nuclear force, and the weak nuclear force. To compare the numerical strengths of the first two, take two particles of the same kind. Since electrons are fundamental particles, they are a good example.
Since both are inverse square law forces, the distance gets canceled when the ratio of the two forces is considered. Instead, the ratio of the electrical and gravitational forces depends on...
Since both are inverse square law forces, the distance gets canceled when the ratio of the two forces is considered. Instead, the ratio of the electrical and gravitational forces depends on...
4.4K
01:27π Electron Effects on Chemical Shift: Overview
1.9K
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...
1.9K
02:35Noncovalent Attractions in Biomolecules
66.1K
Noncovalent attractions are associations within and between molecules that influence the shape and structural stability of complexes. These interactions differ from covalent bonding in that they do not involve sharing of electrons.
Four types of noncovalent interactions are hydrogen bonds, van der Waals forces, ionic bonds, and hydrophobic interactions.
Hydrogen bonding results from the electrostatic attraction of a hydrogen atom covalently bonded to a strong-electronegative atom like oxygen,...
Four types of noncovalent interactions are hydrogen bonds, van der Waals forces, ionic bonds, and hydrophobic interactions.
Hydrogen bonding results from the electrostatic attraction of a hydrogen atom covalently bonded to a strong-electronegative atom like oxygen,...
66.1K
01:30Coulomb's Law
12.5K
Experiments with electric charges have shown that if two objects each have an electric charge, they exert an electric force on each other. The magnitude of the force is linearly proportional to the net charge on each object and inversely proportional to the square of the distance between them. The direction of the force vector is along the imaginary line joining the two objects and is dictated by the signs of the charges involved.
Newton's third law applies to the Coulomb force — the...
Newton's third law applies to the Coulomb force — the...
12.5K
02:54Trends in Lattice Energy: Ion Size and Charge
27.3K
An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure of the strength of this attraction. The lattice energy (ΔHlattice) of an ionic compound is defined as the energy required to separate one mole of the solid into its component gaseous ions. For the ionic solid sodium chloride, the lattice energy is the enthalpy change of the process:
27.3K