TY - JOUR

T1 - Spin-Filtering in a p-Orbital Helical Atomic Chain

AU - Utsumi, Yasuhiro

AU - Kato, Takemitsu

AU - Entin-Wohlman, Ora

AU - Aharony, Amnon

N1 - Publisher Copyright:
© 2022 Wiley-VCH GmbH.

PY - 2022/12

Y1 - 2022/12

N2 - We theoretically analyze spin filtering in two-terminal systems, induced by the spin-orbit interaction (SOI), as a possible origin of the “chirality-induced spin selectivity” (CISS) effect observed experimentally in chiral molecules, such as DNA. Due to Bardarson's theorem, spin filtering cannot be realized in a molecule containing one orbital-channel. However, when two orbitals are involved, SOI can induce spin filtering in a molecule coupled to two terminals without braking time-reversal symmetry. In particular, we provide an example of a (Formula presented.) reflection matrix for a spinful electron passing through a molecule containing two orbital-channels, which complies with Bardarson's theorem and produces a finite spin conductance. As a microscopic toy model realizing a single strand of DNA, we consider a p-orbital helical atomic chain with intra-atomic SOI's and a strong crystalline field along the helix. This model exhibits two-orbital spin filtering: For various parameters preserving the helical symmetry, the model hosts spin asymmetric states carrying pairs of up and down spins propagating in opposite directions. The typical energy scale of the helical states is the product of the intra-atomic SOI and the curvature. The spin filtering mechanism is associated with the intra-atomic SOI, which would be larger than the inter-atomic SOI. In this respect, the present model may be a more likely candidate for the CISS in organic material than other models associated with the inter-atomic SOI.

AB - We theoretically analyze spin filtering in two-terminal systems, induced by the spin-orbit interaction (SOI), as a possible origin of the “chirality-induced spin selectivity” (CISS) effect observed experimentally in chiral molecules, such as DNA. Due to Bardarson's theorem, spin filtering cannot be realized in a molecule containing one orbital-channel. However, when two orbitals are involved, SOI can induce spin filtering in a molecule coupled to two terminals without braking time-reversal symmetry. In particular, we provide an example of a (Formula presented.) reflection matrix for a spinful electron passing through a molecule containing two orbital-channels, which complies with Bardarson's theorem and produces a finite spin conductance. As a microscopic toy model realizing a single strand of DNA, we consider a p-orbital helical atomic chain with intra-atomic SOI's and a strong crystalline field along the helix. This model exhibits two-orbital spin filtering: For various parameters preserving the helical symmetry, the model hosts spin asymmetric states carrying pairs of up and down spins propagating in opposite directions. The typical energy scale of the helical states is the product of the intra-atomic SOI and the curvature. The spin filtering mechanism is associated with the intra-atomic SOI, which would be larger than the inter-atomic SOI. In this respect, the present model may be a more likely candidate for the CISS in organic material than other models associated with the inter-atomic SOI.

KW - Chirality induced spin selectivity effect

KW - Helical symmetry

KW - Spin orbit interaction

KW - Time reversal symmetry

UR - http://www.scopus.com/inward/record.url?scp=85144246161&partnerID=8YFLogxK

U2 - 10.1002/ijch.202200107

DO - 10.1002/ijch.202200107

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AN - SCOPUS:85144246161

SN - 0021-2148

VL - 62

JO - Israel Journal of Chemistry

JF - Israel Journal of Chemistry

IS - 11-12

M1 - e202200107

ER -