Light irradiation controlled spin selectivity in a magnetic helix

The present work critically investigates the interplay between light irradiation, molecular helicity, and electron hopping on spin-selective electron transmission, considering a magnetic helix as the functional element. Depend-ing on the range of electron hopping, short-range and long-range ones, two different kinds of magnetic helices are taken into account. The common examples of these two different ranges of electron hopping are single-stranded DNA and protein molecules respectively. Each magnetic helix is subjected to a circularly polarized light which is applied perpendicular to the helix axis. The transmission spectra associated with up and down spin electrons get significantly modified, resulting in a high degree of spin polarization even when the Fermi energy is placed near the band center. The performance becomes superior with increasing the range of electron hopping. A tight-binding framework is given to describe the system, where the effect of light is incorporated through the minimal coupling approach following the Floquet-Bloch ansatz. All the results are worked out based on the standard Green's function formalism. The degree of spin polarization and its phase can be monitored selectively by means of light. To strengthen the impact of helicity, a comparative study is also made considering twist-free geometry and other twisted magnetic systems. Finally, a brief outline of the possible routes of designing magnetic helices is given, for the sake of completeness of work. Our analysis may provide some insights to achieve controlled spin-based electronic devices using different types of light-driven magnetic helices that are described beyond the conventional nearest-neighbor hopping model.

Automated summary

This work investigates the interaction between light irradiation, molecular helicity, and electron hopping on spin-selective electron transmission. The results show that the range of electron hopping significantly affects spin polarization, with a larger range resulting in better performance. The degree of spin polarization and its phase can be selectively monitored using light. This study provides valuable insights for the development of spin-based electronic devices using light-driven magnetic helices.