Optical Absorption in Twisted Bilayer Graphene

By P. Moon, M. Koshino. 2013

342 citations recorded by the source corpus.

We theoretically study the optical absorption property of twisted bilayer graphenes with various stacking geometries, and demonstrate that the spectroscopic characteristics serve as a fingerprint to identify the rotation angle between two layers. We find that the absorption spectrum almost continuously evolves in changing the rotation angle, regardless of the lattice commensurability. The spectrum is characterized by series of peaks associated with the van Hove singularity, and the peak energies systematically shift with the rotation angle. We calculate the optical absorption in two different frameworks; the tight-binding model and the effective continuum model based on the Dirac equation. For small rotation angles less than $10^\circ$, the effective model well reproduces the low-energy band structure and the optical conductivity of the tight-binding model, and also explains the optical selection rule analytically in terms of the symmetry of the effective Hamiltonian.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/6e9bae44cfad04ac21056f465e8d9c1472ffd62a

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

1. Franco Nori
2. N. Yuan
3. A. Rozhkov
4. A. Rakhmanov
5. A. O. Sboychakov
6. Liang Fu
7. Takashi Koretsune
8. M. Ochi

In Materials Chemistry

1. N. Yuan
2. Liang Fu
3. Franco Nori
4. A. Rozhkov
5. A. O. Sboychakov
6. A. Rakhmanov
7. Takashi Koretsune
8. M. Ochi

Citations in the corpus

• Electronic properties of graphene-based bilayer systems (2015, background): “[445], and found a qualitative agreement between theory and experiment.”
• Interlayer interaction in general incommensurate atomic layers (2015, background): “We actually see additional peak structures due to the interlayer interaction, and these features are consistent with the exact tight-binding calculation for a commensurate bilayer graphene at a similar rotation angle [11].”
• Maximally Localized Wannier Orbitals and the Extended Hubbard Model for Twisted Bilayer Graphene (2018, background): “In a flat TBG, the interlayer distance dðδÞ is constant, and therefore, we have u 1⁄4 u0 [34].”