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Context <p>Chirality-induced spin selectivity (CISS) represents a remarkable quantum phenomenon whereby electron transmission through chiral molecules, such as DNA, becomes intrinsically spin-polarized even in the absence of magnetic fields. Despite extensive experimental verification of static CISS effects, achieving <i>dynamic</i> control over spin polarization remains an open challenge. Terahertz (THz) radiation offers a promising route to externally modulate molecular electronic structure on sub-picosecond timescales. In this study, we develop a theoretical model that unifies THz-driven Floquet dynamics with the spin–orbit coupling inherent to chiral DNA, thereby introducing the concept of Floquet–CISS, a light-induced regime of topologically controlled spin transport in biological helices.</p> Method <p>An effective low-energy Hamiltonian incorporating kinetic motion along the DNA helix, spin–orbit coupling, and the interaction with circularly polarized THz fields was formulated and solved using Floquet theory. The resulting quasi-energy spectra, Berry curvature, and spin polarization were numerically evaluated using plane-wave expansion and LAPACK-based diagonalization. The simulations reveal that THz fields dynamically reshape the Berry curvature, induce tunable spin-split Floquet bands, and produce helicity-dependent spin polarization exceeding 60%. These effects arise entirely from light-matter coupling without magnetic components, establishing DNA as a bio-topological spin filter capable of ultrafast, reversible spin control. The Floquet–CISS mechanism provides a theoretical blueprint for THz-programmable molecular spintronics and paves the way toward optically reconfigurable bio-quantum devices.</p>

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Terahertz-induced Berry curvature control of spin-selective transport in chiral DNA molecules

  • 期刊论文

  • 发表日期：

    2026年2月4日

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  • Moses Udoisoh,
  • Temitope Esther Olajide

摘要

Context

Chirality-induced spin selectivity (CISS) represents a remarkable quantum phenomenon whereby electron transmission through chiral molecules, such as DNA, becomes intrinsically spin-polarized even in the absence of magnetic fields. Despite extensive experimental verification of static CISS effects, achieving dynamic control over spin polarization remains an open challenge. Terahertz (THz) radiation offers a promising route to externally modulate molecular electronic structure on sub-picosecond timescales. In this study, we develop a theoretical model that unifies THz-driven Floquet dynamics with the spin–orbit coupling inherent to chiral DNA, thereby introducing the concept of Floquet–CISS, a light-induced regime of topologically controlled spin transport in biological helices.

Method

An effective low-energy Hamiltonian incorporating kinetic motion along the DNA helix, spin–orbit coupling, and the interaction with circularly polarized THz fields was formulated and solved using Floquet theory. The resulting quasi-energy spectra, Berry curvature, and spin polarization were numerically evaluated using plane-wave expansion and LAPACK-based diagonalization. The simulations reveal that THz fields dynamically reshape the Berry curvature, induce tunable spin-split Floquet bands, and produce helicity-dependent spin polarization exceeding 60%. These effects arise entirely from light-matter coupling without magnetic components, establishing DNA as a bio-topological spin filter capable of ultrafast, reversible spin control. The Floquet–CISS mechanism provides a theoretical blueprint for THz-programmable molecular spintronics and paves the way toward optically reconfigurable bio-quantum devices.