Transverse magnetoconductance in two-terminal chiral spin-selective devices

The phenomenon of chirality induced spin selectivity (CISS) has triggered significant activity in recent years, although many aspects of it remain to be understood. For example, most investigations are focused on spin polarizations collinear to the charge current, and hence longitudinal magnetoconductance (MC) is commonly studied in two-terminal transport experiments. Very little is known about the transverse spin components and transverse MC - their existence, as well as any dependence of this component on chirality. Furthermore, the measurement of the CISS effect via two-terminal MC experiments remains a controversial topic. Detection of this effect in the linear response regime is debated, with contradicting reports in the literature. Finally, the potential influence of the well-known electric magnetochiral effect on CISS remains unclear. To shed light on these issues, in this work we have investigated the bias dependence of the CISS effect using planar carbon nanotube networks functionalized with chiral molecules. We find that (a) transverse MC exists and exhibits tell-tale signs of the CISS effect, (b) transverse CISS MC vanishes in the linear response regime establishing the validity of Onsager's relation in two-terminal CISS systems, and finally (c) the CISS signal remains present even in the absence of electric magneto chiral effects, suggesting the existence of an alternative physical origin of CISS MC.

Automated summary

The phenomenon of chirality induced spin selectivity (CISS) has attracted significant attention in recent years, but there are still many aspects that need to be understood. Most of the research has focused on spin polarizations collinear to the charge current, leaving the existence and dependence of transverse spin components and transverse magnetoconductance (MC) largely unknown. The detection of the CISS effect via two-terminal MC experiments is still controversial, with conflicting reports in the literature. Furthermore, the potential influence of electric magnetochiral effects on CISS remains unclear. In this work, the bias dependence of the CISS effect was investigated using planar carbon nanotube networks functionalized with chiral molecules. The study revealed the existence of transverse MC and provided insight into the behavior of CISS in different regimes.