Spin-polaronic effects in electric shuttling in a single molecule transistor with magnetic leads

Abstract

© 2020 Elsevier B.V. Current–voltage characteristics of a spintromechanical device, in which spin-polarized electrons tunnel between magnetic leads with anti-parallel magnetization through a single-level movable quantum dot, are calculated. New exchange- and electromechanical coupling-induced (spin-polaronic) effects that determine strongly nonlinear current–voltage characteristics were found. In the low-voltage regime of electron transport the voltage-dependent and exchange field-induced displacement of the quantum dot towards the source electrode leads to a nonmonotonic behavior of the differential conductance, which demonstrates the lifting of spin-polaronic effects by an electric field. At high voltages the onset of electron shuttling results in a drop of the current and a negative differential conductance, caused by a mechanically induced increase of the tunnel resistances and an exchange field-induced suppression of spin-flips caused by an external magnetic field. The dependence of these predicted spin effects on the oscillation frequency of the dot and the strength of electron–electron correlations is discussed