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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• Pseudo-magnetic field-induced ultra-slow carrier dynamics in periodically strained graphene
• Controlling Valley-Polarisation in Graphene via Tailored Light Pulses
• Two-dimensional crystals on adhesive substrates subjected to uniform transverse pressure
• All-Optical Ultrafast Valley Switching in Two-Dimensional Materials
• Cornertronics in Two-Dimensional Second-Order Topological Insulators
• Valley polarization braiding in strained graphene
• A Non-Hermitian Moiré Valley Filter
• Strain-induced pseudo-magnetic field in $\alpha -{\mathcal{T}}_3$ lattice
• Electron dynamics in strained graphene
• Valley filtering in strain-induced $\alpha$-${\mathcal{T}}_3$ quantum dots
• Convenient Peierls phase choice for periodic atomistic systems under magnetic field
• Graphene nanodrums as valleytronic devices
• Topological valley crystals in a photonic Su-Schrieffer-Heeger (SSH) variant
• Effective magnetic field induced by inhomogeneous Fermi velocity in strained honeycomb structures
• Valley current generation using biased bilayer graphene dots
• Probing valley filtering effect by Andreev reflection in zigzag graphene nanoribbon
• Graphene membrane as a pressure gauge
• Tunable valley filtering in dynamically strained $\alpha$-${\mathcal{T}}_3$ lattices
• Electronic transport in bent carbon nanotubes
• A 50/50 electronic beam splitter in graphene nanoribbons as a building block for electron optics
• Triaxially strained suspended graphene for large-area pseudo-magnetic fields
• 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
• Pseudo Electric Field and Pumping Valley Current in Graphene Nano-bubbles
• Chaos based Berry phase detector
• Switching valley filtered current directions in multi-terminal graphene systems
• Tuning magnetism in graphene nanoribbons via strain and adatoms
• Valley filters, accumulators, and switches induced in graphene quantum dots by lines of adsorbed hydrogen atoms
• Origins of Valley Current Reversal in Partially Overlapped Graphene Layers
• Creation and control of valley currents in graphene by few cycle light pulses
• Pseudo-magnetic fields in square lattices
• Ultrafast all-optical generation of pure spin and valley currents
• Quantum Nonlinear Acoustic Hall Effect and Inverse Acoustic Faraday Effect in Dirac Insulators
• Programmable Kondo Effect Formed by Landau Levels
• Thermoelectric transport in graphene under strain fields modeled by Dirac oscillators
• Energy symmetry and interlayer wave function ratio of tunneling electrons in partially overlapped graphene
• High-purity valley-polarized currents induced by bichromatic optical fields in two-dimensional materials
• Tunnel Valley Current Filter in the Partially Overlapped Graphene under the Vertical Electric Field
• Scalable tight-binding model for strained graphene
• Strain-induced stacking transition in bilayer graphene
• Pseudomagnetic fields and strain engineering: graphene on GaN nanowires