Superconducting phase-difference-free route to second-order topological superconductivity in Rashba-Dresselhaus bilayers

Abstract

We propose a superconducting phase-difference-free approach to realizing second-order topological superconductivity in bilayers of coupled two-dimensional electron gases. In this setup, one layer hosts Rashba and the other hosts Dresselhaus spin-orbit coupling. With proximity-induced conventional s-wave pairing of the identical phase and a perpendicular Zeeman field, the two layers effectively emulate chiral p-wave superconductors of opposite chirality. The misalignment between the Rashba and Dresselhaus spin textures, combined with interlayer tunneling, gives rise to mass domain walls at the sample corners, which bind robust Majorana zero modes protected by a mirror-symmetry-graded Z2 invariant. Unlike previous proposals, our scheme requires no superconducting phase difference between the layers, thereby eliminating a major experimental challenge. Furthermore, the spatial positions of the Majorana corner modes can be electrically controlled by engineering orthogonal Rashba channels via ferroelectric polarization. This electrical tunability naturally enables the movement and exchange of Majorana modes in multiterminal geometries, positioning Rashba-Dresselhaus bilayers as a practical and versatile platform for higher-order topological superconductivity and Majorana-based quantum computation.

Source-reported materials — not catalogue approval

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