Spin filtering with poly-T wrapped single wall carbon nanotubes

Area of Science:

• Spintronics
• Materials Science
• Biophysics

Background:

• Spin filtering is crucial for spintronics, but conventional magnetic materials offer limited efficiency (~50%).
• Chirality Induced Spin Selectivity (CISS) in chiral molecules like DNA presents a promising alternative for efficient spin manipulation.
• Existing CISS studies often use specific DNA sequences, prompting exploration of other chiral systems.

Purpose of the Study:

• To investigate spin polarization in single-wall carbon nanotubes (SWCNTs) coated with poly-T DNA.
• To evaluate the efficiency of this DNA-SWCNT system as a spin filter.
• To explore the potential of chemically tailored chiral systems for spintronics.

Main Methods:

• Fabrication of SWCNTs helically wrapped with single-stranded poly-T DNA.
• Characterization using magnetoresistance measurements to quantify spin polarization.
• Analysis of results in the context of Rashba spin-orbit interaction and CISS.

Main Results:

• The DNA-SWCNT system exhibited a significant spin polarization of approximately 80%.
• This efficiency surpasses previously reported values for other DNA sequences.
• The observed spin polarization is attributed to the helical potential of DNA inducing Rashba spin-orbit interaction.

Conclusions:

• Helically wrapped poly-T DNA on SWCNTs act as highly efficient spin filters, surpassing conventional magnetic materials.
• This system enables magnetic-free, chemically tunable, and highly localized spin polarization.
• Potential for extreme miniaturization and integration of spintronic devices and circuits.