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arXiv · 1609.05769

Valley filtering by a line-defect in graphene: quantum interference and inversion of the filter effect

Lucas H. Ingaramo·Luis E. F. Foa Torres
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Abstract

Valley filters are crucial to any device exploiting the valley degree of freedom. By using an atomistic model, we analyze the mechanism leading to the valley filtering produced by a line-defect in graphene and show how it can be inverted by external means. Thanks to a mode decomposition applied to a tight-binding model we can resolve the different transport channels in k-space while keeping a simple but accurate description of the band structure, both close and further away from the Dirac point. This allows the understanding of a destructive interference effect (Fano resonance or antiresonance) on the p-side of the Dirac point leading to a reduced conductance. We show that in the neighborhood of this feature the valley filtering can be reversed by changing the occupations with a gate voltage, the mechanism is explained in terms of a valley-dependent Fano resonance splitting. Our results open the door for an enhanced control of valley transport in graphene-based devices.

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Lucas H. Ingaramo, Luis E. F. Foa Torres. 2016-09-19. Valley filtering by a line-defect in graphene: quantum interference and inversion of the filter effect. https://doi.org/10.1088/0953-8984/28/48/485302

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