Graphene Nanobubbles as Valley Filters and Beamsplitters

Abstract

The low energy band structure of graphene has two inequivalent valleys at K and K' points of the Brillouin zone. The possibility to manipulate this valley degree of freedom defines the field of valleytronics, the valley analogue of spintronics. A key requirement for valleytronic devices is the ability to break the valley degeneracy by filtering and spatially splitting valleys to generate valley polarized currents. Here we suggest a way to obtain valley polarization using strain-induced inhomogeneous pseudomagnetic fields (PMF) which act differently on the two valleys. Notably, the suggested method does not involve external magnetic fields, or magnetic materials, as previous proposals. In our proposal the strain is due to experimentally feasible nanobubbles (but any local deformation would do): the associated PMFs lead to different real space trajectories for K and K' electrons, thus allowing the two valleys to be addressed individually. In this way, graphene nanobubbles can be exploited in both valley filtering and valley splitting devices, and our simulations reveal that a number of different functionalities are possible depending on the deformation field.

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Cited by in corpus (20)

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• Light-Induced Valleytronics in Pristine Graphene
• Tuning the pseudospin polarization of graphene by a pseudo-magnetic field
• Strain controlled valley filtering in multi-terminal graphene structures
• Pseudo-magnetic field-induced ultra-slow carrier dynamics in periodically strained graphene
• Controlling Valley-Polarisation in Graphene via Tailored Light Pulses
• Valley polarization braiding in strained graphene
• Electron dynamics in strained graphene
• Valley filtering in strain-induced $\alpha$-${\mathcal{T}}_3$ quantum dots
• Valley current generation using biased bilayer graphene dots
• Effective magnetic field induced by inhomogeneous Fermi velocity in strained honeycomb structures
• Probing valley filtering effect by Andreev reflection in zigzag graphene nanoribbon
• Graphene membrane as a pressure gauge
• A 50/50 electronic beam splitter in graphene nanoribbons as a building block for electron optics
• Strong plasmon-phonon splitting and hybridization in 2D materials revealed through a self-energy approach
• Emergence of strain-induced moiré patterns and pseudo-magnetic field confined states in graphene
• Chaos based Berry phase detector
• Switching valley filtered current directions in multi-terminal graphene systems
• Valley filters, accumulators, and switches induced in graphene quantum dots by lines of adsorbed hydrogen atoms
• Pseudomagnetic fields and strain engineering: graphene on GaN nanowires