Chiral-Induced Spin Selectivity and Non-equilibrium Spin Accumulation in Molecules and Interfaces: A First-Principles Study

21 November 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Electrons moving through chiral molecules are selected according to their spin orientation and the helicity of the molecule, an effect known as chiral induced spin selectivity (CISS). The underlying physical mechanism is not yet completely understood. To help elucidate this mechanism, a non-equilibrium Green’s function method, combined with a Landauer approach and density functional theory, is applied to carbon helices contacted by gold electrodes, resulting in spin polarization of transmitted electrons. Interestingly, spin polarization is also observed in the non-equilibrium electronic structure of the junctions. While this spin polarization is small, its sign changes with the direction of current and with the handedness of the molecule. While these calculations were performed with a pure exchange-correlation functional, previous studies suggest that computationally more expensive hybrid functionals may lead to considerably larger spin polarization in the electronic structure. Thus, nonequilibrium spin polarization could be a key component in understanding the CISS mechanism.


density functional theory
Chiral induced spin selectivity
molecular spintronics
coherent tunneling
spin polarization

Supplementary materials

Supporting Information
Computational details, optimization, and comparison of computational parameters and exchange-correlation functionals; total and spin-resolved transmission functions; I-V curves; spin densities for larger bias voltages, different current directions and helicities, and larger electrodes; potential drop at larger bias voltages and for larger electrodes; noncollinear Mulliken spin populations; spin polarization for junctions with one Ni electrode; input files and atomic coordinates for all calculations.


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