Ultra-short suspended single-wall carbon nanotube transistors

Island, Joshua O.; Tayari, V.; Yigen, Serap; McRae, A. C.; Champagne, A. R.

doi:10.1063/1.3670055

Cited by 13 publications

(29 citation statements)

References 26 publications

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“…(22), i.e., the correction due to C x is second order in the small quantity R/L. The coupling strength C x might gain importance and significantly contribute to the T * 2 in ultrashort CNT QDs [38][39][40], where L ∼ R, or for electrons that occupy a highly excited longitudinal mode of a QD.…”

Section: Inhomogeneous Dephasing Of a Valley Qubitmentioning

confidence: 99%

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Orbital hyperfine interaction and qubit dephasing in carbon nanotube quantum dots

Csiszár

Pályi

2014

Phys. Rev. B

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Hyperfine interaction (HF) is of key importance for the functionality of solid-state quantum information processing, as it affects qubit coherence and enables nuclear-spin quantum memories. In this work, we complete the theory of the basic HF mechanisms (Fermi contact, dipolar, orbital) in carbon nanotube quantum dots by providing a theoretical description of the orbital HF. We find that orbital HF induces an interaction between the nuclear spins of the nanotube lattice and the valley degree of freedom of the electrons confined in the quantum dot. We show that the resulting nuclear-spin-electron-valley interaction (i) is approximately of Ising type; (ii) is essentially local, in the sense that a radius-and dot-length-independent atomic interaction strength can be defined; and (iii) has an atomic interaction strength that is comparable to the combined strength of the Fermi contact and dipolar interactions. We argue that orbital HF provides a new decoherence mechanism for single-electron valley qubits and spin-valley qubits in a range of multivalley materials. We explicitly evaluate the corresponding inhomogeneous dephasing time T * 2 for a nanotube-based valley qubit.

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Section: Inhomogeneous Dephasing Of a Valley Qubitmentioning

confidence: 99%

“…The correction of the form ∝ τ 3 I x is small since C x ≪ C z . Note that the coupling strength C x might gain importance in the case λ ∼ R, e.g., in ultrashort CNT QDs [38][39][40] or in QDs where the electron occupies a highly excited, short-wavelength longitudinal mode.…”

Section: Introductionmentioning

confidence: 99%

Orbital hyperfine interaction and qubit dephasing in carbon nanotube quantum dots

Csiszár

Pályi

2014

Phys. Rev. B

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“…Theory says that metallic nanotubes can develop a band gap due to symmetry breaking of the underlying graphene lattice from strains, twists and curvature. The magnitude of this gap is predicted to be around tens of milli-electron volts but zero field gaps of an order of a magnitude larger have been reported [19][20][21]. Perhaps most intriguingly though, in the single particle picture, these gaps should vanish at the Dirac field as the nanotube quantization line is pushed to the Dirac point of the underlying graphene band structure resulting in a truly metallic nanotube.…”

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confidence: 97%

Interaction-Driven Giant Orbital Magnetic Moments in Carbon Nanotubes

et al. 2018

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Carbon nanotubes continue to be model systems for studies of confinement and interactions. This is particularly true in the case of so-called "ultra-clean" carbon nanotube devices offering the study of quantum dots with extremely low disorder. The quality of such systems, however, has increasingly revealed glaring discrepancies between experiment and theory. Here we address the outstanding anomaly of exceptionally large orbital magnetic moments in carbon nanotube quantum dots. We perform low temperature magneto-transport measurements of the orbital magnetic moment and find it is up to seven times larger than expected from the conventional semiclassical model. Moreover, the magnitude of the magnetic moment monotonically drops with the addition of each electron to the quantum dot directly contradicting the widely accepted shell filling picture of single-particle levels. We carry out quasiparticle calculations, both from first principles and within the effectivemass approximation, and find the giant magnetic moments can only be captured by considering a self-energy correction to the electronic band structure due to electron-electron interactions.arXiv:1809.08347v1 [cond-mat.mes-hall]

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“…The solubility of ultra short nanotubes in organic solvents, acids and water at the level of 2 weight % was revealed [4][5][6] that is an important achievement for the creation of functional nanomaterials. The experimental success opens up a way for usage of usSWCNTs for applications such as light detectors, photovoltaics, field-effect transistors and sensors with highly optimized characteristics [1,3,[7][8][9]. Lots of theoretical researches of carbon nanotubes demonstrate that the decrease their length less than 10 nm causes of great changes in the electronic structure and fundamental parameters such as the energy gap (E LH ) between the lowest unoccupied (LUMO) and the highest occupied (HOMO) molecular orbitals, ionization potential (IP), electron affinity (EA), work function [10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Spin-dependent energy gap oscillations in the ultra-short carbon nanotube (5, 5)

Tuchin¹,

Попов²,

Glushkov³

et al. 2015

J. Phys.: Conf. Ser.

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Abstract.Results of the numerical simulation of an electronic structure of an ultrashort singlewalled carbon nanotube (5, 5) at singlet and triplet states were presented. An antiphase energy gap oscillation on the length of the ultrashort nanotube (5, 5) at singlet and triplet states was revealed. It was found that the ground state of the nanotube is singlet, herewith the energy of the singlet-triplet transition corresponds to the energy value of visible and IR-radiation.

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Ultra-short suspended single-wall carbon nanotube transistors

Cited by 13 publications

References 26 publications

Orbital hyperfine interaction and qubit dephasing in carbon nanotube quantum dots

Orbital hyperfine interaction and qubit dephasing in carbon nanotube quantum dots

Interaction-Driven Giant Orbital Magnetic Moments in Carbon Nanotubes

Spin-dependent energy gap oscillations in the ultra-short carbon nanotube (5, 5)

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