Related Experiment Video
Updated: Jun 29, 2025
13:56
Probe Type II Band Alignment in One-Dimensional Van Der Waals Heterostructures Using First-Principles Calculations
Published on: October 12, 2019
7.6K
Flat bands without twists: periodic holey graphene
Abdiel de Jesús Espinosa-Champo1,2,3, Gerardo G Naumis2
1Posgrado de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 20-364 01000 Ciudad de México, Mexico.
Summary
Researchers explored holey graphene (HG) and discovered flat electronic bands emerge due to sublattice imbalance. This provides a simpler method for creating flat bands, potentially leading to novel quantum phases.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Chemistry
Background:
- Holey graphene (HG) is utilized for synthesizing high-purity crystalline materials.
- Understanding the electronic properties of patterned graphene structures is crucial for advanced material design.
Purpose of the Study:
- To investigate the electronic properties of holey graphene with periodic lattice holes.
- To demonstrate the emergence of flat bands and topological properties in HG.
- To present a facile method for generating flat bands and exploring correlated quantum phases.
Main Methods:
- Theoretical exploration of electronic properties in HG with periodic lattice holes.
- Analysis of band structures, sublattice imbalance, and symmetry breaking (path-exchange and inversion).
- Derivation of a low-energy Hamiltonian for the central bands.
Main Results:
- Periodic lattice holes in graphene induce sublattice imbalance, leading to the formation of flat electronic bands.
- Breaking inversion symmetry opens gaps and induces topological bands with nonzero Berry curvature.
- Dirac cones fold into the superlattice Brillouin zone, resulting in gap formation periodicity (n≡0 mod 3).
- The system exhibits behavior analogous to effective α-T3 graphene.
Conclusions:
- A simple protocol for reliably obtaining flat bands in holey graphene is presented.
- This method offers an accessible route to engineer flat bands, which enhance electron-electron correlation effects.
- HG provides a promising platform for realizing highly correlated quantum phases, alternative to complex twisted systems.
Related Concept Videos
01:01Energy Bands in Solids
849
Isolated atoms have discrete energy levels that are well described by the Bohr model. And, it quantifies the energy of an electron in a hydrogen atom as En. Higher quantum numbers 'n' yield less negative, closer electron energy levels.
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...
849
02:35Band Theory
15.1K
When two or more atoms come together to form a molecule, their atomic orbitals combine and molecular orbitals of distinct energies result. In a solid, there are a large number of atoms, and therefore a large number of atomic orbitals that may be combined into molecular orbitals. These groups of molecular orbitals are so closely placed together to form continuous regions of energies, known as the bands.
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
15.1K
03:51Molecular Orbital Theory II
19.1K
Molecular Orbital Energy Diagrams
19.1K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
42.5K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
42.5K
02:52VSEPR Theory and the Basic Shapes
68.3K
Overview of VSEPR Theory
68.3K
03:24Hybridization of Atomic Orbitals I
47.0K
The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals. The new orbitals that...
47.0K