Spin Filtering with Poly-T Wrapped Single Wall Carbon Nanotubes

TL;DR

This study demonstrates that helically wrapped poly-T DNA on single wall carbon nanotubes can achieve high spin polarization (~80%) through the CISS effect, enabling efficient, miniaturized spintronic devices without magnetic components.

Contribution

It introduces a novel DNA-wrapped nanotube system that exhibits enhanced spin filtering efficiency, surpassing previous DNA-based systems, and highlights its potential for spintronic applications.

Findings

Achieved ~80% spin polarization in DNA-wrapped nanotubes.

Observed larger spin polarization than previous DNA systems.

Proposed chemical control of spin polarization for device integration.

Abstract

Spin filtering is an essential operation in spintronics that allows creation and detection of spin polarized carriers. Transition metal ferromagnets are used as spin filters in most cases, though their spin filtering efficiency is only around ~50%, thereby limiting the efficiency of spintronic devices. Recently, chiral systems such as DNA have been shown to exhibit efficient spin filtering, a phenomenon often dubbed as "chirality induced spin selectivity" (CISS). In this work, we consider single wall carbon nanotubes helically wrapped with single stranded poly-T DNA. By magnetoresistance measurements we show that this system exhibits significant spin polarization of ~80%, which could be attributed to the Rashba spin-orbit interaction induced by the inversion asymmetric helical potential of the DNA. Observed spin polarization is larger than that reported before for d(GT)15 strands. Such systems allow tailoring spin polarization by chemical means and also allow extremely localized creation and detection of spin polarization without any magnetic element and could lead to extreme miniaturization and compact integration of spintronic devices and circuits.