Effect of gate voltage on spin transport along $\alpha$-helical protein

TL;DR

This study explores how applying a gate voltage influences spin transport and polarization in alpha-helical proteins, revealing tunable spin filtration and robustness against disorder, with implications for molecular spintronics.

Contribution

It demonstrates the significant impact of gate voltage on spin transport in alpha-helical proteins, including enhanced spin filtration and oscillating polarization behavior, advancing understanding of chiral-induced spin selectivity.

Findings

Gate voltage significantly affects conductance and spin polarization.

Spin filtration efficiency can be improved by tuning the gate voltage.

Spin polarization increases with molecular length and oscillates with gate voltage.

Abstract

Recently, the chiral-induced spin selectivity in molecular systems has attracted extensive interest among the scientific communities. Here, we investigate the effect of the gate voltage on spin-selective electron transport through the $\alpha$-helical peptide/protein molecule contacted by two nonmagnetic electrodes. Based on an effective model Hamiltonian and the Landauer-B\"uttiker formula, we calculate the conductance and the spin polarization under an external electric field which is perpendicular to the helix axis of the $\alpha$-helical peptide/protein molecule. Our results indicate that both the magnitude and the direction of the gate field have a significant effect on the conductance and the spin polarization. The spin filtration efficiency can be improved by properly tuning the gate voltage, especially in the case of strong dephasing regime. And the spin polarization increases monotonically with the molecular length without the gate voltage, which is consistent with the recent experiment, and presents oscillating behavior in the presence of the gate voltage. In addition, the spin selectivity is robust against the dephasing, the on-site energy disorder, and the space angle disorder under the gate voltage. Our results could motivate further experimental and theoretical works on the chiral-based spin selectivity in molecular systems.