Particle localization on helical nanoribbons: Quantum analog of the Coriolis effect

Abstract

We derive the Schr\"odinger equation for a particle confined to the surface of a normal and a binormal helical nanoribbon, obtain the quantum potentials induced by their respective curved surface geometries, and study the localized states of the particle for each ribbon. When the particle momentum satisfies a certain geometric condition, the particle localizes near the inner edge for a normal ribbon, and on the central helix for a binormal ribbon. This result suggests the presence of a pseudo-force that pushes the particle transversely along the width of the ribbon. We show that this phenomenon can be interpreted as a quantum analog of the Coriolis effect, which causes a transverse deflection of a classical particle moving in a rotating frame. We invoke Ehrenfest's theorem applicable to localized states and identify the quantized angular velocities of the rotating frames for the two ribbons. If the particle is an electron, its localization at a specific width gives rise to a Hall-like voltage difference across the ribbon's width. However, unlike in the Hall effect, its origin is not an applied magnetic field, but the ribbon's curved surface geometry. When a normal helical ribbon is mechanically flipped to a binormal configuration in a periodic fashion, it results in a periodic electron transport from the inner edge to the center, giving rise to a quantum AC voltage. This can be used for designing nanoscale electromechanical devices. Quantum transport on a helical nanoribbon can be controlled by tuning the bends and twists of its surface, suggesting diverse applications in biopolymers and nanotechnology.