Partial positive refraction in asymmetric Veselago lenses of uniaxially strained graphene

Abstract

Asymmetric Veselago lenses (AVLs) can be created from ballistic $p$-$n$ and $n$-$p$-$n$ homojunctions of uniaxially strained graphene. This atypical converging electron flow emerges by applying uniaxial tension out of the device's symmetry axes. A part of electron flow needs to be positively refracted for focusing in an asymmetric spot, whose location is tunable with the strain. In AVLs, Klein tunneling is angularly shifted regards to the normal incidence. This perfect transmission occurs at the straight line that connects the point source and focus, which is unaffected by variation of the Fermi level and barrier's width. Moreover, the mirror symmetry breaking by the strain also causes the asymmetry in Fabry-Pérot interference. The novel electron optical laws allow to evidence that reflected and refracted electrons in AVLs lie on the same straight line with opposite group velocities and pseudo-spins. Unlike isotropic graphene, electrons under normal incidence present backscattering, angles of reflection and refraction different to zero. The average particle transmission is higher (lower) than isotropic case when the tensile strain is increased near (far away) the normal direction. These results may be useful for designing strain-bendable probing tips in scanning tunneling microscopes.

10 pages, 5 figures

References in corpus (28)

• The electronic properties of graphene
• Chiral tunneling and the Klein paradox in graphene
• A tight-binding approach to uniaxial strain in graphene
• Andreev reflection and Klein tunneling in graphene
• Quantum interference and Klein tunneling in graphene heterojunctions
• All-graphene integrated circuits via strain engineering
• Veselago Lens for Electrons: Focusing and Caustics in Graphene p-n Junctions
• Selective transmission of Dirac electrons and ballistic magnetoresistance of \textit{n-p} junctions in graphene
• Evidence of Klein tunneling in graphene p-n junctions
• Transport measurements across a tunable potential barrier in graphene
• Nonlinear elasticity of monolayer graphene
• Klein Backscattering and Fabry-Perot Interference in Graphene Heterojunctions
• Electron Beam Supercollimation in Graphene Superlattices
• Generation of pure bulk valley current in graphene
• Coherent control of single electrons: a review of current progress
• Gate-controlled Guiding of Electrons in Graphene
• Conductance of p-n-p graphene structures with 'air-bridge' top gates
• Valleytronics in merging Dirac cones: All-electric-controlled valley filter, valve and universal reversible logic gate
• Conductance asymmetry of graphene pn junction
• Spin-valley filtering in strained graphene structures with artificially induced carrier mass and spin-orbit coupling
• Creating and Steering Highly Directional Electron Beams in Graphene
• Current-Voltage Characteristics of Weyl Semimetal Semiconducting Devices, Veselago Lenses and Hyperbolic Dirac Phase
• Fabry-Pérot resonances in a graphene/hBN Moiré superlattice
• Landau Levels in Uniaxially Strained Graphene: A Geometrical Approach
• Classical and quantum magneto-oscillations of current flow near a p-n junction in graphene
• Controlling electron flow in anisotropic Dirac materials heterojunctions: a super-diverging lens
• Two-dimensional Fermionic Hong-Ou-Mandel Interference with Weyl Fermions
• Perfect transmission of 3D massive Kane fermions in HgCdTe Veselago lenses

Cited by in corpus (12)

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• Phase-space representation of Landau and electron coherent states for uniaxially strained graphene
• Valley-dependent time evolution of coherent electron states in tilted anisotropic Dirac materials
• Gradient-index electron optics in graphene pn junctions
• Anomalous Floquet tunneling in uniaxially strained graphene
• Phosphorene pnp junctions as perfect electron waveguides
• Kekulé Induced Valley Birefringence and Skew Scattering in Graphene
• Schrödinger-type 2D coherent states of magnetized uniaxially strained graphene
• Complex Supersymmetry in Graphene
• Extended transfer matrix method for electron transmission in anisotropic 2D materials: Interplay of strain and (a)periodicity of potentials
• Klein tunneling in deformed honeycomb-dice lattice: from massless to massive particles