Spin-Dependent Electron Transmission Model for Chiral Molecules in Mesoscopic Devices

TL;DR

This paper introduces a theoretical electron transmission model for chiral molecules in mesoscopic devices, clarifying the role of the CISS effect and proposing experimental setups to distinguish it from other magnetic signals.

Contribution

The paper presents a new model that explains the spin-dependent electron transmission in chiral molecules and suggests specific multi-terminal measurements to identify the CISS effect.

Findings

Chirality-dependent spin transmission involves spin-flip electron reflection.

More than two terminals are necessary to probe the CISS effect in linear regimes.

Proposed multi-terminal nonlocal measurements can differentiate CISS from other effects.

Abstract

Various device-based experiments have indicated that electron transfer in certain chiral molecules may be spin-dependent, a phenomenon known as the Chiral Induced Spin Selectivity (CISS) effect. However, due to the complexity of these devices and a lack of theoretical understanding, it is not always clear to what extent the chiral character of the molecules actually contributes to the magnetic-field-dependent signals in these experiments. To address this issue, we report here an electron transmission model that evaluates the role of the CISS effect in two-terminal and multi-terminal linear-regime electron transport experiments. Our model reveals that for the CISS effect, the chirality-dependent spin transmission is accompanied by a spin-flip electron reflection process. Furthermore, we show that more than two terminals are required in order to probe the CISS effect in the linear regime. In addition, we propose two types of multi-terminal nonlocal transport measurements that can distinguish the CISS effect from other magnetic-field-dependent signals. Our model provides an effective tool to review and design CISS-related transport experiments, and to enlighten the mechanism of the CISS effect itself.