Boundary-induced violation of the Dirac fermion parity and its signatures in local and global tunneling spectra of graphene
arXiv:0810.0632 · doi:10.1103/PhysRevB.79.195422
Abstract
Extended defects in graphene, such as linear edges, break the translational invariance and can also have an impact on the symmetries specific to massless Dirac-like quasiparticles in this material. The paper examines the consequences of a broken Dirac fermion parity in the framework of the effective boundary conditions varying from the Berry-Mondragon mass confinement to a zigzag edge. The parity breaking reflects the structural sublattice asymmetry of zigzag-type edges and is closely related to the previously predicted time-reversal symmetric edge states. We calculate the local and global densities of the edge states and show that they carry a specific polarization, resembling, to some extent, that of spin-polarized materials. The lack of the parity leads to a nonanalytical particle-hole asymmetry in the edge-state properties. We use our findings to interpret recently observed tunneling spectra in zigzag-terminated graphene. We also propose a graphene-based tunneling device where the particle-hole asymmetric edge states result in a strongly nonlinear conductance-voltage characteristics, which could be used to manipulate the tunneling transport.
8 pages, 5 figures, to be published in Phys. Rev. B
References in corpus (15)
- Quantum Spin Hall Insulator State in HgTe Quantum Wells
- Energy Gaps in Graphene Nanoribbons
- Chiral tunneling and the Klein paradox in graphene
- Chaotic Dirac billiard in graphene quantum dots
- Valley filter and valley valve in graphene
- Electronic States of Graphene Nanoribbons
- The Quantum Spin Hall Effect: Theory and Experiment
- Magnetic Correlations at Graphene Edges
- Scanning Tunneling Spectroscopy of Graphene on Graphite
- Spin currents in rough graphene nanoribbons: Universal fluctuations and spin injection
- Edge States and the Quantized Hall Effect in Graphene
- Symmetry Classes in Graphene Quantum Dots: Universal Spectral Statistics, Weak Localization, and Conductance Fluctuations
- Stabilization mechanism of edge states in graphene
- Dirac fermion quantization on graphene edges: Isospin-orbit coupling, zero modes and spontaneous valley polarization
- Fine structure of the local pseudogap and Fano effect for superconducting electrons near a zigzag graphene edge