Spin Filtering in DNA-like Materials
The chiral induced spin selectivity (CISS) is an intriguing phenomenon where the chirality of DNA molecules helps to produce a current of electrons that are spin polarized. Although such effect may benefit applications in quantum logic, sensing, and storage devices, such as magnetic memories, some aspects of the CISS are not fully understood yet. This research is clarifying how the length of DNA molecules impacts the production of spin-polarized currents through the CISS. The numerical methods were implemented in an in-house quantum transport MATLAB code provided by Prof. Low’s group to address the question. The numerical results showed that if the fermi level is in the valence band of the one-dimensional DNA-like chiral crystal, the production of spin-polarized electrons by the CISS is rapidly varying, with dominantly spin up electrons for a large fraction of DNA molecule lengths considered. When the fermi level is at the conduction band, the CISS produces a tiny amount of spin down electrons for all DNA molecule lengths. Our research offers incremental help in understanding the behavior of transmitting electron spins in DNA molecules of different lengths, which might contribute to further scientific research in the future. In addition, it also provides a systematic path for utilizing the CISS for producing spins in chiral DNA-like materials, offering a perspective for utilizing these materials in technological applications in spintronics.