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Valley-dependent electron optics using quantum dots in bilayer graphene

Fereshte Ildarabadi and Stephen R. Power*

  • *Contact author: stephen.r.power@dcu.ie
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Phys. Rev. B 114, 245404 – Published 2 October, 2026

DOI: https://doi.org/10.1103/6byg-rx71

Abstract

Electrostatically defined quantum dots (QDs) with layer-antisymmetric gating in Bernal-stacked bilayer graphene (BLG) open a local gap and generate a masslike term with opposite sign in the two valleys, producing strongly valley-dependent scattering without magnetic fields, strain, or spin-orbit coupling. Building on this mechanism, we propose a tunable platform based on such QDs for valley-dependent electron optics in BLG. Using a four-band continuum model and a generalized multiple-scattering formalism, we analyze the scattering of Gaussian electron beams from single-dot and multidot architectures and compute valley-resolved currents and angular profiles. A single dot produces distinct valley-dependent deflection, while multidot configurations enable enhanced control: identical-dot arrays act as valley splitters, whereas oppositely gated pairs function as valley filters. Combining these elements yields tunable generation, steering, and filtering of highly valley-polarized currents with strong suppression of forward transmission. The required energy scales, gate asymmetries, and device dimensions are within experimentally accessible regimes for dual-gated BLG, establishing quantum-dot arrays as a realistic platform for controllable valley-resolved electron optics.

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Phys. Rev. B 114, 245404– Published 2 October, 2026
  • Received 12 June 2026
  • Revised 2 September 2026
  • Accepted 14 September 2026
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