Transport Hamiltonians for helical spintronics: Derivation from symmetries

Area of Science:

• Condensed Matter Physics
• Quantum Chemistry
• Materials Science

Background:

• Helical structures exhibit unique spin-dependent transport properties.
• Symmetry principles offer powerful constraints on electronic behavior.

Purpose of the Study:

• To derive real-space tight-binding Hamiltonians for helical structures based on symmetry.
• To investigate the role of chirality in spin-orbit coupling and transport.

Main Methods:

• Derivation of Hamiltonians from line-group symmetries and time-reversal invariance.
• Nearest-neighbor parametrization for π-like orbitals.
• Slater-Koster interpretation of couplings and identification of spin-orbit pathways.

Main Results:

• Symmetry-complete model for intra- and inter-strand transport in helices.
• Demonstration that inter-strand hopping is purely spin-active in symmetric double helices.
• Emergence of Rashba-like terms as an intrinsic consequence of helix chirality.

Conclusions:

• The derived model provides a controlled baseline for quantum transport in DNA-like helices.
• Chirality intrinsically generates spin-orbit effects, crucial for understanding spin textures.
• Symmetry-based modeling offers a powerful approach to predicting spin-dependent phenomena.