Valley filter and valley valve in graphene

By A. Rycerz, J. Tworzydło, C. Beenakker. 2006

1,405 citations recorded by the source corpus.

The potential of graphene for carbon electronics rests on the possibilities offered by its unusual band structure to create devices that have no analogue in silicon-based electronics1,2. Conduction and valence bands in graphene form conically shaped valleys, touching at a point called the Dirac point. There are two inequivalent Dirac points in the Brillouin zone, related by time-reversal symmetry. Intervalley scattering is suppressed in pure samples3,4,5. The independence and degeneracy of the valley degree of freedom suggests that it might be used to control an electronic device6, in much the same way as the electron spin is used in spintronics7 or quantum computing8. A key ingredient for ‘valleytronics’ would be a controllable way of occupying a single valley in graphene, thereby producing a valley polarization. Here we propose such a valley filter, based on a ballistic point contact with zigzag edges. The polarity can be inverted by local application of a gate voltage to the point contact region. Two valley filters in series may function as an electrostatically controlled valley valve, representing a zero-magnetic-field counterpart to the familiar spin valve.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/7c0d34b87f3c48577e6e0567265bd618a3b0c6f8

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In Atomic and Molecular Physics, and Optics

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Citations in the corpus

New perspectives for Rashba spin-orbit coupling. (2015, background): “the generation of a transverse charge neutral current induced by the Berry curvature, which could be used as a new functional degree of freedom [125], [126].”
Charge transport in disordered graphene-based low dimensional materials (2008, background): “For example, a valley-valve effect (blocking of the electrical current by a p-n junction) has been demonstrated theoretically in zigzag ribbons in the presence of an external potential [50].”
High frequency electric field induced nonlinear effects in graphene (2013, background): “This constitutes a two-state degree of freedom, which was suggested to be used in valleytronics [22].”
Topological origin of subgap conductance in insulating bilayer graphene (2010, background): “Many fascinating phenomena originating from the properties of edge states in graphene layers have been predicted theoretically, such as electric-field tunable magnetism [1] and valley-dependent transport [2, 3].”
Production, properties and potential of graphene (2010, neutral): “[167-169] and the observation of Andreev reflections.”
Nobel Lecture: Graphene: Materials in the Flatland (2011, background): “This allows us to talk about a completely new and unexplored direction in electronics: strain engineering of electronic structure (Pereira and Neto, 2009) and valleytronics (Rycerz et al., 2007; Martin et al., 2008; Low and Guinea, 2010).”
A first-principles study on gas sensing properties of graphene and Pd-doped graphene (2015, neutral): “[4] A.”
Electronic transport in two-dimensional graphene (2010, background): “…its spin Cho et al. (2007); Han et al. (2009); Hill et al. (2006); Huertas-Hernando et al. (2006, 2009); Józsa et al. (2009); Tombros et al. (2007) or valley Rycerz et al. (2007b) degeneracy or by patterning gates with a periodic super-potential (Brey and Fertig, 2009a; Park et al., 2008).”