Valley-selective Klein tunneling through superlattice barrier in graphene
arXiv:1909.01870 · doi:10.1103/PhysRevApplied.14.014039
Abstract
Graphene electrons feature a pair of massless Dirac cones of opposite pseudospin chirality at two valleys. Klein tunneling refers to the intriguing capability of these chiral electrons to penetrate through high and wide potential barrier. The two valleys have been treated independently in the literature, where time reversal symmetry dictates that neither the normal incidence transmission nor the angle-averaged one can have any valley polarization. Here we show that, when intervalley scattering by barrier is accounted, graphene electrons normally incident at a superlattice barrier can experience a fully valley-selective Klein tunneling, i.e. perfect transmission in one valley, and perfect reflection in the other. Intervalley backscattering creates staggered pseudospin gaps in the superlattice barrier, which, combined with the valley contrast in pseudospin chirality, determines the valley polarity of Klein tunneling. The angle averaged transmission can have a net valley polarization of 20% for a 5-period barrier, and exceed 75% for a 20-period barrier. Our finding points to an unexpected opportunity to realize valley functionalities in graphene electronics.
arXiv comment15 pages, 4 figures
References in corpus (27)
- Chiral tunneling and the Klein paradox in graphene
- Valley contrasting physics in graphene: magnetic moment and topological transport
- Valley filter and valley valve in graphene
- Quantum interference and Klein tunneling in graphene heterojunctions
- Valley Dependent Optoelectronics from Inversion Symmetry Breaking
- Veselago Lens for Electrons: Focusing and Caustics in Graphene p-n Junctions
- Atomically thin boron nitride: a tunnelling barrier for graphene devices
- Detecting Topological Currents in Graphene Superlattices
- Anisotropic behaviors of massless Dirac fermions in graphene under periodic potential
- Topological confinement in bilayer graphene
- Graphene valley filter using a line defect
- Generation and detection of pure valley current by electrically induced Berry curvature in bilayer graphene
- New Generation of Massless Dirac Fermions in Graphene under External Periodic Potentials
- Valley Chern Numbers and Boundary Modes in Gapped Bilayer Graphene
- Edge states in Graphene: from gapped flat band to gapless chiral modes
- Gate-tunable Topological Valley Transport in Bilayer Graphene
- Ballistic transport exceeding 28 μm in CVD grown graphene
- Strain-induced pseudo-magnetic field for novel graphene electronics
- Electron optics with ballistic graphene junctions
- Electron Beam Supercollimation in Graphene Superlattices
- Valley-dependent Brewster angles and Goos-Hanchen effect in strained graphene
- Emerging Zero Modes for Graphene in a Periodic Potential
- A valley valve and electron beam splitter
- Nonlinear valley and spin currents from Fermi pocket anisotropy in 2D crystals
- Quantized conductance in an AlAs 2D electron system quantum point contact
- Valley and spin pump by scattering at non-magnetic disorders
- Switchable valley functionalities of an junction in 2D semiconductors