Inelastic electron scattering from a helical potential: transverse polarization and the structure factor in the single scattering approximation

Varela, Solmar; Medina, Ernesto; López, Floralba; Mújica, Vladimiro

doi:10.1088/0953-8984/26/1/015008

Cited by 36 publications

(44 citation statements)

References 17 publications

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“…Because of its prominent character and potential technological impact, we offer a brief survey of the theoretical attempts to understand the CISS phenomenon in terms of technology and basic science. Earlier theoretical treatises motivated by transmission electron measurements (Ray et al, 2006;Göhler et al, 2011) addressed CISS in terms of scattering approaches (Yeganeh et al, 2009;Medina et al, 2012;Eremko and Loktev, 2013;Gerstin, Kaasbjerg, and Nitzan, 2013;Varela et al, 2014). Since our focus is on electron transport, we refrain from following that direction here.…”

Section: B Chirality-induced Spin Selectivitymentioning

confidence: 99%

Advances and challenges in single-molecule electron transport

et al. 2020

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Electronic transport properties of single-molecule junctions have been widely measured by several techniques, including mechanically controllable break junctions, electromigration break junctions, and by means of scanning tunneling microscopes. In parallel, many theoretical tools have been developed and refined for describing such transport properties and for obtaining numerical predictions. Most prominent among these theoretical tools are those based upon density functional theory. In this review, theory and experiment are critically compared, and this confrontation leads to several important conclusions. The theoretically predicted trends nowadays reproduce the experimental findings well for series of molecules with a single well-defined control parameter, such as the length of the molecules. The quantitative agreement between theory and experiment usually is less convincing, however. Two main sources for the quantitative discrepancies can be identified. Experimentally, the atomic structure of the junction typically realized in the measurement is not well known, so simulations rely on plausible scenarios. In theory, correlation effects can be included only in approximations that are difficult to control for experimentally relevant situations. Therefore, one typically expects qualitative agreement with present modeling tools; in exceptional cases a quantitative agreement has already been achieved. For further progress, benchmark systems are required that are sufficiently well defined by experiment to allow quantitative testing of the approximation schemes underlying the theoretical modeling. Several key experiments can be identified suggesting that the present description may even be qualitatively incomplete in some cases. Such key experimental observations and their current models are also discussed here, leading to several suggestions for extensions of the models toward including dynamic image charges, electron correlations, and polaron formation.

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Section: B Chirality-induced Spin Selectivitymentioning

confidence: 99%

Advances and challenges in single-molecule electron transport

et al. 2020

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“…Here y 0 = ε 0 − J 0 e ik 0 and we substituted r |χ r = − |χ in + |ψ 1,1 and t |χ t = |ψ M,N from Eqs. (14). To solve Eqs.…”

Section: Scattering Problemmentioning

confidence: 99%

Spin-dependent transport through a chiral molecule in the presence of spin-orbit interaction and nonunitary effects

Matityahu¹,

Utsumi²,

Aharony³

et al. 2016

Phys. Rev. B

137

151

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Recent experiments have demonstrated the efficacy of chiral helically shaped molecules in polarizing the scattered electron spin, an effect termed as chiral-induced spin selectivity (CISS). Here we solve a simple tight-binding model for electron transport through a single helical molecule, with spin-orbit interactions on the bonds along the helix. Quantum interference is introduced via additional electron hopping between neighboring sites in the direction of the helix axis. When the helix is connected to two one-dimensional single-mode leads, time-reversal symmetry prevents spin polarization of the outgoing electrons. One possible way to retrieve such a polarization is to allow leakage of electrons from the helix to the environment, via additional outgoing leads. Technically, the leakage generates complex site self-energies, which break unitarity. As a result, the electron waves in the helix become evanescent, with different decay lengths for different spin polarizations, yielding a net spin polarization of the outgoing electrons, which increases with the length of the helix (as observed experimentally). A maximal polarization can be measured at a finite angle away from the helix axis.

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“…7,8 The experimental setup, where electrons are photoemitted from the surface, is understood theoretically in terms of multiple scattering through the chiral target in the presence spin-orbit coupling (SOC). [8][9][10][11] The theoretical model requires interference between scalar potential events and spin-orbit coupled scattering. Chiral structure and SOC define an energy window in the range of 1-10 eV in which the electron spin is effectively polarized.…”

Section: Introductionmentioning

confidence: 99%

Continuum model for chiral induced spin selectivity in helical molecules

Medina

Gonzalez-Arraga

Finkelstein-Shapiro

et al. 2015

The Journal of Chemical Physics

Self Cite

113

135

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A minimal model is exactly solved for electron spin transport on a helix. Electron transport is assumed to be supported by well oriented p(z) 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(z) - π(z) coupling via interbase p(x,y) - p(z) 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.

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Inelastic electron scattering from a helical potential: transverse polarization and the structure factor in the single scattering approximation

Cited by 36 publications

References 17 publications

Advances and challenges in single-molecule electron transport

Advances and challenges in single-molecule electron transport

Spin-dependent transport through a chiral molecule in the presence of spin-orbit interaction and nonunitary effects

Continuum model for chiral induced spin selectivity in helical molecules

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