### Abstract

A minimal model is exactly solved for electron spin transport on a helix. Electron transport is assumed to be supported by well oriented p<inf>z</inf> type orbitals on base molecules forming a staircase of definite chirality. In a tight binding interpretation, the spin-orbit coupling (SOC) opens up an effective π<inf>z</inf> - π<inf>z</inf> coupling via interbase p<inf>x,y</inf> - p<inf>z</inf> hopping, introducing spin coupled transport. The resulting continuum model spectrum shows two Kramers doublet transport channels with a gap proportional to the SOC. Each doubly degenerate channel satisfies time reversal symmetry; nevertheless, a bias chooses a transport direction and thus selects for spin orientation. The model predicts (i) which spin orientation is selected depending on chirality and bias, (ii) changes in spin preference as a function of input Fermi level and (iii) back-scattering suppression protected by the SO gap. We compute the spin current with a definite helicity and find it to be proportional to the torsion of the chiral structure and the non-adiabatic Aharonov-Anandan phase. To describe room temperature transport, we assume that the total transmission is the result of a product of coherent steps.

Original language | English (US) |
---|---|

Article number | 194308 |

Journal | Journal of Chemical Physics |

Volume | 142 |

Issue number | 19 |

DOIs | |

State | Published - May 21 2015 |

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### ASJC Scopus subject areas

- Physics and Astronomy(all)
- Physical and Theoretical Chemistry

### Cite this

*Journal of Chemical Physics*,

*142*(19), [194308]. https://doi.org/10.1063/1.4921310

**Continuum model for chiral induced spin selectivity in helical molecules.** / Medina, Ernesto; González-Arraga, Luis A.; Finkelstein-Shapiro, Daniel; Berche, Bertrand; Mujica, Vladimiro.

Research output: Contribution to journal › Article

*Journal of Chemical Physics*, vol. 142, no. 19, 194308. https://doi.org/10.1063/1.4921310

}

TY - JOUR

T1 - Continuum model for chiral induced spin selectivity in helical molecules

AU - Medina, Ernesto

AU - González-Arraga, Luis A.

AU - Finkelstein-Shapiro, Daniel

AU - Berche, Bertrand

AU - Mujica, Vladimiro

PY - 2015/5/21

Y1 - 2015/5/21

N2 - A minimal model is exactly solved for electron spin transport on a helix. Electron transport is assumed to be supported by well oriented pz type orbitals on base molecules forming a staircase of definite chirality. In a tight binding interpretation, the spin-orbit coupling (SOC) opens up an effective πz - πz coupling via interbase px,y - pz hopping, introducing spin coupled transport. The resulting continuum model spectrum shows two Kramers doublet transport channels with a gap proportional to the SOC. Each doubly degenerate channel satisfies time reversal symmetry; nevertheless, a bias chooses a transport direction and thus selects for spin orientation. The model predicts (i) which spin orientation is selected depending on chirality and bias, (ii) changes in spin preference as a function of input Fermi level and (iii) back-scattering suppression protected by the SO gap. We compute the spin current with a definite helicity and find it to be proportional to the torsion of the chiral structure and the non-adiabatic Aharonov-Anandan phase. To describe room temperature transport, we assume that the total transmission is the result of a product of coherent steps.

AB - A minimal model is exactly solved for electron spin transport on a helix. Electron transport is assumed to be supported by well oriented pz type orbitals on base molecules forming a staircase of definite chirality. In a tight binding interpretation, the spin-orbit coupling (SOC) opens up an effective πz - πz coupling via interbase px,y - pz hopping, introducing spin coupled transport. The resulting continuum model spectrum shows two Kramers doublet transport channels with a gap proportional to the SOC. Each doubly degenerate channel satisfies time reversal symmetry; nevertheless, a bias chooses a transport direction and thus selects for spin orientation. The model predicts (i) which spin orientation is selected depending on chirality and bias, (ii) changes in spin preference as a function of input Fermi level and (iii) back-scattering suppression protected by the SO gap. We compute the spin current with a definite helicity and find it to be proportional to the torsion of the chiral structure and the non-adiabatic Aharonov-Anandan phase. To describe room temperature transport, we assume that the total transmission is the result of a product of coherent steps.

UR - http://www.scopus.com/inward/record.url?scp=84929650619&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84929650619&partnerID=8YFLogxK

U2 - 10.1063/1.4921310

DO - 10.1063/1.4921310

M3 - Article

AN - SCOPUS:84929650619

VL - 142

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 19

M1 - 194308

ER -