CISS Effect: A Magnetoresistance Through Inelastic Scattering.

Abstract

One of the manifestations of chirality-induced spin selectivity is the magnetoresistance (MR) in two-terminal transport measurements on molecular junctions. This paper investigates the effect of spin–orbit coupling in the leads on the polarization of the transmission. A helicene molecule between two gold contacts is studied using a tight binding model. To study the occurrence of MR, which is prohibited in coherent transport, as a consequence of the Büttiker reciprocity, we add Büttiker probes to the system in order to incorporate inelastic scattering effects. We show that for a strict two-terminal system without inelastic scattering, the MR is strictly zero in the linear and nonlinear regimes. We show that for a two-terminal system with inelastic scattering, a nonzero MR does appear in the nonlinear regime, reaching values of the order of 0.1%. Our calculations show that for a two-terminal system respecting time-reversal symmetry and charge conservation, a nonzero MR can only be obtained through inelastic scattering. However, spin–orbit coupling in the leads in combination with inelastic scattering modeled with the Büttiker probe method cannot explain the magnitude of the MR measured in experiments.