Carrier localization and magnetoresistance in DNA-functionalized carbon nanotubes

Helical functionalization of carbon nanotubes using DNA strands can polarize carrier spins through chirality induced spin selectivity (or CISS) effect. Detection of this effect using transport experiments unravels an underlying magnetoresistance effect, origin of which is not well understood. In the present study, we investigate this effect, a fundamental understanding of which is crucial for the potential use of this system in spintronic devices. The conduction mechanism has been found to be in the strongly localized regime due to DNA functionalization, with the observed magnetoresistance originating from the interference effects between the forward and backward hopping paths. CISS-induced spin polarization has been estimated to increase the carrier localization length by an order of magnitude in the low temperature range and it affects the magnetoresistance effect in a non-trivial way that is not observed in conventional systems.

Automated summary

Functionalizing carbon nanotubes with DNA strands in a helical manner can polarize carrier spins through the CISS effect. The conduction mechanism is strongly localized due to DNA functionalization, and the observed magnetoresistance arises from interference effects between different hopping paths. CISS-induced spin polarization increases carrier localization length significantly in the low temperature range, impacting magnetoresistance in a non-trivial way not seen in conventional systems.