Konschuh, S. and Gmitra, M. and Kochan, D. and Fabian, J. (2012) Theory of spin-orbit coupling in bilayer graphene. PHYSICAL REVIEW B, 85 (11): 115423. ISSN 1098-0121, 1550-235X
Full text not available from this repository.Abstract
A theory of spin-orbit coupling in bilayer graphene is presented. The electronic band structure of the AB bilayer in the presence of spin-orbit coupling and a transverse electric field is calculated from first principles using the linearized augmented plane-wave method implemented in the WIEN2K code. The first-principles results around the K points are fitted to a tight-binding model. The main conclusion is that the spin-orbit effects in bilayer graphene derive essentially from the single-layer spin-orbit coupling which comes almost solely from the d orbitals. The intrinsic spin-orbit splitting (anticrossing) around the K points is about 24 mu eV for the low-energy valence and conduction bands, which are closest to the Fermi level, similarly as in the single-layer graphene. An applied transverse electric field breaks space inversion symmetry and leads to an extrinsic (also called Bychkov-Rashba) spin-orbit splitting. This splitting is usually linearly proportional to the electric field. The peculiarity of graphene bilayer is that the low-energy bands remain split by 24 mu eV independently of the applied external field. The electric field, instead, opens a semiconducting band gap separating these low-energy bands. The remaining two high-energy bands are spin split in proportion to the electric field; the proportionality coefficient is given by the second intrinsic spin-orbit coupling, whose value is 20 mu eV. All the band-structure effects and their spin splittings can be explained by our tight-binding model, in which the spin-orbit Hamiltonian is derived from symmetry considerations. The magnitudes of intra- and interlayer couplings-their values are similar to the single-layer graphene ones-are determined by fitting to first-principles results.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | GRAPHITE; SPINTRONICS; CARBON; STATE; |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Theroretical Physics Physics > Institute of Theroretical Physics > Chair Professor Richter > Group Jaroslav Fabian |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 18 May 2020 08:51 |
| Last Modified: | 18 May 2020 08:51 |
| URI: | https://pred.uni-regensburg.de/id/eprint/19045 |
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