Scheme for topological single electron pumping assisted by Majorana fermions

Abstract

Single electron pumping based on the topological property of Majorana fermions (MFs), which specify the parity of electron number, is proposed. The setup consists of a quantum dot (QD) and two NOT gates each with four nanotopological superconductors (TSs) connected by constriction junctions and an additional vortex located in the loop of TSs. Operation is performed by gate voltages at constriction junctions. The condition of QD energy for sequential electron pumping is derived in terms of interactions among TSs, indicating that the QD energy may lie outside the energies of electrodes, which is unique as compared with other existing pumping mechanisms. The essence of the present topological single electron pumping lies in the nonlocal property of MFs, which makes crossing between quasiparticle levels possible and electrically controllable. The operation of the NOT gate is demonstrated, explicitly solving the time-dependent Bogoliubov-de Gennes equation for a microscopic model.