The valley filter efficiency of monolayer graphene and bilayer graphene line defect model

Abstract

In addition to electron charge and spin, novel materials host another degree of freedom, the valley. For a junction composed of valley filter sandwiched by two normal terminals, we focus on the valley efficiency under disorder with two valley filter models based on monolayer and bilayer graphene. Applying the transfer matrix method, valley resolved transmission coefficients are obtained. We find that: i) under weak disorder, when the line defect length is over about $15\mathrm{nm}$, it functions as a perfect channel (quantized conductance) and valley filter (totally polarized); ii) in the diffusive regime, combination effects of backscattering and bulk states assisted intervalley transmission enhance the conductance and suppress the valley polarization; iii) for very long line defect, though the conductance is small, polarization is indifferent to length. Under perpendicular magnetics field, the characters of charge and valley transport are only slightly affected. Finally we discuss the efficiency of transport valley polarized current in a hybrid system.

6 figures

References in corpus (15)

• The electronic properties of graphene
• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Chiral tunneling and the Klein paradox in graphene
• Valley polarization in MoS2 monolayers by optical pumping
• The Valley Hall Effect in MoS2 Transistors
• Valley filter and valley valve in graphene
• Valley Dependent Optoelectronics from Inversion Symmetry Breaking
• Detecting Topological Currents in Graphene Superlattices
• Topological confinement in bilayer graphene
• Edge states in Graphene: from gapped flat band to gapless chiral modes
• Electronic Highways in Bilayer Graphene
• Valley-Hall Kink and Edge States in Multilayer Graphene
• Localized states at zigzag edges of bilayer graphene
• One-dimensional quantum channel in a graphene line defect
• Conductivity of graphene: How to distinguish between samples with short and long range scatterers

Cited by in corpus (3)

• NiCl3 Monolayer: Dirac Spin-Gapless Semiconductor and Chern Insulator
• Probing valley filtering effect by Andreev reflection in zigzag graphene nanoribbon
• Valley filters, accumulators, and switches induced in graphene quantum dots by lines of adsorbed hydrogen atoms