Wurm, Juergen and Wimmer, Michael and Richter, Klaus (2012) Symmetries and the conductance of graphene nanoribbons with long-range disorder. PHYSICAL REVIEW B, 85 (24): 245418. ISSN 1098-0121,
Full text not available from this repository.Abstract
We study the conductance of graphene nanoribbons with long-range disorder. Due to the absence of intervalley scattering from the disorder potential, time-reversal symmetry (TRS) can be effectively broken even without a magnetic field, depending on the type of ribbon edge. Even though armchair edges generally mix valleys, we show that metallic armchair nanoribbons possess a hidden pseudovalley structure and an effectively broken TRS. In contrast, semiconducting armchair nanoribbons inevitably mix valleys and restore TRS. As a result, in strong disorder metallic armchair ribbons exhibit a perfectly conducting channel, but semiconducting armchair ribbons exhibit ordinary localization. TRS is also effectively broken in zigzag nanoribbons in the absence of valley mixing. However, we show that intervalley scattering in zigzag ribbons is significantly enhanced and TRS is restored even for smooth disorder if the Fermi energy is smaller than the potential amplitude. The symmetry properties of disordered nanoribbons are also reflected in their conductance in the diffusive regime. In particular, we find suppression of weak localization and an enhancement of conductance fluctuations in metallic armchair and zigzag ribbons without valley mixing. In contrast, semiconducting armchair and zigzag ribbons with valley mixing exhibit weak localization behavior.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | CARBON NANOTUBES; TRANSPORT; FIELDS; STATE; EDGE; |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Theroretical Physics > Chair Professor Richter > Group Klaus Richter |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 12 May 2020 05:52 |
| Last Modified: | 12 May 2020 05:52 |
| URI: | https://pred.uni-regensburg.de/id/eprint/18589 |
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