| AVS 66th International Symposium & Exhibition | |
| 2D Materials | Tuesday Sessions |
| Session 2D+EM+MI+NS-TuA |
| Session: | Properties of 2D Materials including Electronic, Magnetic, Mechanical, Optical, and Thermal Properties II |
| Presenter: | Daiara Faria, Ohio University / Universidade do Estado do Rio de Janeiro |
| Authors: | D. Faria, Ohio University / Universidade do Estado do Rio de Janeiro C. León, Brigham Young University L. Lima, Universidade Rural do Rio de Janeiro, Brazil A. Latgé, Universidade Federal Fluminense, Brazil N. Sandler, Ohio University |
| Correspondent: | Click to Email |
The coupling between electronic and mechanical properties in 2D materials has become an important tool to control valleytronics. Graphene experiments have been reported with common deformations such as membrane bending that induces strain in the samples [1]. It has also been shown that strain affects charge distributions and graphene transport properties. Motivated by these responses, we have studied the effect of folds and wrinkles in graphene. New ’edge’-like states along the graphene folded region, that are valley polarized, were found and explored [2]. To take advantage of the existence of these new states, it would be desirable to separate their contribution from the continuum extended states that make graphene a semimetal.
Here we present a theoretical study of folds effects on a graphene membrane in the quantum Hall regime. We show that the addition of an external magnetic field allows the isolation of the valley polarized edge states in energy and in real space. Local density of state calculations in the deformation region predict the valley split peaks, as observed in recent experimental [3]. Using recursive Green’s function method, we are able to reveal new extra conducting channels due to the "new edges” at the deformation region. These extra conducting channels could be detected in transport measurements.
A discussion is presented to bring attention on the role of the deformation parameters on the graphene quantum Hall regime and their relations with the magnetic lengths. With this in mind, we perform an analytic study based on the continuum (Dirac) description of electrons in graphene. In this model, the deformation is considered as a perturbation to the Landau Level states. The results show the existence of two different regimes, characterized by the ratio between the magnetic length and the deformation width (γ = lB/b). For γ<1 the magnetic confinement allows the electrons to follow the strain potential profile. In this regime, the spatial separation between the polarized currents is larger. This could encourage the design of devices where contacts can efficiently detect these polarized currents.
[1] Y. Jiang et al., Nano Lett. 17, 2839 (2017).
[2] R. Carrillo-Bastos et al., PRB 94, 125422 (2016).
[3] S. Li, arXiv:1812.04344.