Helicoidal Fields and Spin Polarized Currents in Carbon Nanotube–DNA Hybrids

Diniz, G. S.; Latgé, A.; Ulloa, Sergio E.

doi:10.1103/physrevlett.108.126601

Cited by 44 publications

(61 citation statements)

References 31 publications

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“…Thus we proceed to explain this effect using the framework of spin-polarized carrier generation and detection. The model that we use is based on a recent theoretical work [16] that predicted spin polarized conductance for ssDNA-wrapped SWCNTs, which originates due to the Rashba spin-orbit coupling mediated by the inversion asymmetric helicoidal electric field of the ssDNA strands.…”

Section: Resultsmentioning

confidence: 99%

“…Thus these mechanisms alone cannot explain the large spin dependent barrier height discussed above. Therefore this work should be viewed within the framework of the Rashba spin-orbit interaction induced by the inversion asymmetric helicoidal electric field of the ssDNA [16,17] . It is to be noted that similar unusual large splitting between the two spin states has been observed in spin selective conduction through double stranded DNA [9] .…”

Section: Resultsmentioning

confidence: 99%

“…As these electrons traverse through the ssDNA wrapped SWCNT, it has been shown in ref. [16] that they accumulate some net spin polarization (say P). If this happens, the accumulated spin polarization P can be sensed by the ferromagnetic Ni "spin detector" at the other end of the device.…”

Section: Resultsmentioning

confidence: 99%

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Spin Filtering through Single‐Wall Carbon Nanotubes Functionalized with Single‐Stranded DNA

Alam

Pramanik

2015

Adv Funct Materials

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Abstract.High spin polarization materials or spin filters are key components in spintronics, a niche subfield of electronics where carrier spins play a functional role. Carrier transmission through these materials is "spin selective" i.e. these materials are able to discriminate between "up" and "down" spins. Common spin filters include transition metal ferromagnets and their alloys, with typical spin selectivity (or, polarization) ~ 50% or less. Here we consider carrier transport in an archetypical one-dimensional molecular hybrid in which a single wall carbon nanotube (SWCNT) is wrapped around by single stranded deoxyribonucleic acid (ssDNA). By magnetoresistance measurements we show that this system can act as a spin filter with maximum spin polarization approaching ~ 74% at low temperatures, significantly larger than transition metals under comparable conditions. Inversion asymmetric helicoidal potential of the charged ssDNA backbone induces a Rashba spin-orbit interaction in the SWCNT channel and polarizes carrier spins. Our results are consistent with recent theoretical work that predicted spin dependent conductance in ssDNA-SWCNT hybrid. Ability to generate highly spin polarized carriers using molecular functionalization can lead to magnet-less and contactless spintronic devices in the future. This can eliminate the conductivity mismatch problem and open new directions for research in organic spintronics. 2 1. Introduction.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Spin Filtering through Single‐Wall Carbon Nanotubes Functionalized with Single‐Stranded DNA

Alam

Pramanik

2015

Adv Funct Materials

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“…Additionally, the CISS effect opens new opportunities for using chiral molecules in spintronic applications and could provide a deeper understanding of the spin effects in biological processes. For the above reasons, there has been considerable interest in the spin transport along various chiral systems including dsDNA (8)(9)(10)(11), single-stranded DNA (ssDNA) (12)(13)(14)(15), and carbon nanotubes (16). However, no spin selectivity was measured in the ssDNA above the experimental noise (5).…”

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confidence: 99%

Spin-dependent electron transport in protein-like single-helical molecules

Guo

Sun

2014

Proc. Natl. Acad. Sci. U.S.A.

197

249

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We report on a theoretical study of spin-dependent electron transport through single-helical molecules connected by two nonmagnetic electrodes, and explain the experiment of significant spin-selective phenomenon observed in α-helical protein and the contradictory results between the protein and single-stranded DNA. Our results reveal that the α-helical protein is an efficient spin filter and the spin polarization is robust against the disorder. These results are in excellent agreement with recent experiments [Mishra D, et al. (2013) S pintronics is a multidisciplinary field that manipulates the electron spin transport in solid-state systems and has been receiving much attention among the physics, chemistry, and biology communities (1-4). Recent experiments have made significant progress in this research field, finding that doublestranded DNA (dsDNA) molecules are highly efficient spin filters (5-7). This chiral-induced spin selectivity (CISS) is surprising because the DNA molecules are nonmagnetic and their spin-orbit couplings (SOCs) are small. Additionally, the CISS effect opens new opportunities for using chiral molecules in spintronic applications and could provide a deeper understanding of the spin effects in biological processes. For the above reasons, there has been considerable interest in the spin transport along various chiral systems including dsDNA (8-11), single-stranded DNA (ssDNA) (12-15), and carbon nanotubes (16). However, no spin selectivity was measured in the ssDNA above the experimental noise (5).Very recently, spin-dependent electron transmission and electrochemical experiments were performed on bacteriorhodopsinan α-helical protein of which the structure is single helicalembedded in purple membrane which was physisorbed on a variety of substrates (17). It was reported by means of two distinct techniques that the electrons transmitted through the membrane are spin polarized, independent of the experimental environments, implying that this α-helical protein can exhibit the ability of spin filtering. Meanwhile, a chiral-based magnetic memory device was fabricated by using self-assembled monolayer of another α-helical protein called polyalanine (18). All of these results seem to be inconsistent with previous experiments' conclusions that the single-stranded helical molecules, such as ssDNA, may not polarize the electrons (5). We note that the electron transport/transfer has been widely investigated in many proteins (19)(20)(21)(22)(23)(24)(25)(26). However, to our knowledge, the underlying physics is still unclear for spin-selective phenomenon observed in the α-helical protein and for the contradictory behaviors between the protein and the ssDNA.In this paper, we propose a model Hamiltonian to explore the spin transport through single-helical molecules connected by two nonmagnetic electrodes, and provide an unambiguous physical mechanism for efficient spin selectivity observed in the protein and for the contrary experimental results between the protein and the ssDNA. Our results reveal that t...

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“…Assuming unpolarized charge currents flowing from left to right, the spin-dependent conductance G LR σσ (E) is proportional to the probability that an electron with spin σ and energy E in the left contact reaches right contact with spin σ . This probability can be calculated using the Green function formalism [24,25]. The spin polarization of the conductance in the y-direction is defined as…”

Section: B Model and Methodsmentioning

confidence: 99%

Defect-enhanced Rashba spin-polarized currents in carbon nanotubes

et al. 2017

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The production of spin-polarized currents in pristine carbon nanotubes with Rashba spin-orbit interaction has been shown to be very sensitive to the symmetry of the tubes and the geometry of the setup. Here we analyze the role of defects on the spin quantum conductances of metallic carbon nanotubes due to an external electric field. We show that localized defects, such as adsorbed hydrogen atoms or pentagon-heptagon pairs, increase the Rashba spin-polarized current. Moreover, this enhancement takes place for energies closer to the Fermi energy as compared to the response of pristine tubes. Such increment can be even larger when several equally spaced defects are introduced into the system. We explore different arrangements of defects, showing that for certain geometries there are flips of the spin-polarized current and even transport suppression. Our results indicate that spin valve devices at the nanoscale may be achieved via defect engineering in carbon nanotubes.

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Helicoidal Fields and Spin Polarized Currents in Carbon Nanotube–DNA Hybrids

Cited by 44 publications

References 31 publications

Spin Filtering through Single‐Wall Carbon Nanotubes Functionalized with Single‐Stranded DNA

Spin Filtering through Single‐Wall Carbon Nanotubes Functionalized with Single‐Stranded DNA

Spin-dependent electron transport in protein-like single-helical molecules

Defect-enhanced Rashba spin-polarized currents in carbon nanotubes

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