Many-body effects on the electronic and optical properties of strained semiconducting carbon nanotubes

Spataru, Catalin D.; Léonard, François

doi:10.1103/physrevb.88.045404

Cited by 13 publications

(16 citation statements)

References 38 publications

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“…Examples include interaction with a substrate, other nanostructures, polymers or DNA encapsulation, metallic contacts, doping, applied electric or magnetic fields, applied strain, alignment in periodic arrays, and so on 1 . Both electronic and optical properties of CNTs are expected to be altered by such environmental and dimensionality effects [2][3][4][5] .…”

Section: Introductionmentioning

confidence: 99%

Electronic and optical gap renormalization in carbon nanotubes near a metallic surface

Spataru

2013

Phys. Rev. B

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Renormalization of quasiparticles and excitons in carbon nanotubes (CNTs) near a metallic surface has been studied within a many-body formalism using an embedding approach newly implemented in the GW and Bethe-Salpeter methods. The quasiparticle bandgap renormalization in semiconducting CNTs is found to scale as −1/(2ha), with ha the apparent nanotube height, and it can exceed half an eV. Also, the binding energy of excitons is reduced dramatically -by as much as 75%-near the surface. Compensation between quasiparticle and excitonic effects results in small changes in the optical gap. The important role played by the nanotube screening response in establishing these effects is emphasized and a simple electrostatic model with no adjustable parameters explains the results of state-of-the-art calculations and generalizes them to a large variety of CNTs.

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Section: Introductionmentioning

confidence: 99%

Electronic and optical gap renormalization in carbon nanotubes near a metallic surface

Spataru

2013

Phys. Rev. B

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“…Intrinsic effects are related to the change in the electronic bands of the individual CNT (or the interactions of its bands) with respect to external perturbation, such as electronic and optical excitations and strain . In Figure (upper row), this is given for single and aligned CNTs.…”

Section: Cnt Strain Sensor Technologymentioning

confidence: 99%

“…The CNTs are applied to increase the signal‐to‐noise ratio of classical MEMS, which are traditionally read out capacitively. There are also different attempts to measure the effect of strain on the optical transitions of a CNT—followed by theoretical predictions of the strain dependence of optical transitions . However, these devices are technologically challenging …”

Section: Cnt Strain Sensor Technologymentioning

confidence: 99%

Carbon Nanotubes for Mechanical Sensor Applications

Wagner

Blaudeck

Meszmer

et al. 2019

Physica Status Solidi (a)

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Herein, the evolution of carbon nanotubes (CNTs) as functional material in nano‐ and microelectromechanical systems (N/MEMS) is featured. Introducing material morphologies for the CNTs in a homologue series (single CNTs—bundles, fibers, yarns—networks and thin films), different concepts for mechanical sensors based on the intrinsic and extrinsic properties of the CNT materials are introduced (piezoresistive effect, strain‐induced band bending, charge tunneling). In a rigorous theoretical treatment, the limits of the achievable sensor performance (i.e., gauge factor) are derived and discussed in the context of applications. A careful literature survey shows that highest sensitivity is reached for devices exploiting the intrinsic transport properties of single CNTs. For reliability tests of such sensor systems made from nanomaterials and classical MEMS, the specimen‐centered approach (SCA) is introduced to give viable insights into the structure property relationships and failure modes of CNT mechanical sensors. CNT actuation occurs on the macro‐, micro‐, and nanoscales via atomic force microscopy, electrostatic gating, integration in N/MEMS systems, or through substrate bending.

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“…This approach is simpler than applying the more expensive GW approximation, but the scissorshift correction is often evaluated from experiments, and the correction is very unlikely to be available for strained or bent structures relevant for industrial applications. In bulk crystals, GW yields a nearly constant shift to the fundamental gap of semilocal DFT even for strained structures, but this is not necessarily true any more for low-dimensional systems 7,8 . This difference is a consequence of enhanced many-body effects present at low-dimensionality.…”

Section: Introductionmentioning

confidence: 98%

Opening band gaps of low-dimensional materials at the meta-GGA level of density functional approximations

Neupane,

Tang,

Nepal

et al. 2021

Preprint

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The quasiparticle band structure can be properly described by the GW approximation, at an increased computational cost. Semilocal density functionals up to the generalized gradient approximation (GGA) level cannot compete with the accuracy of hybrid-based approximations or GW.Meta-GGA density functionals with a strong dependence on the kinetic energy density ingredient can potentially give wider band gaps compared to GGA's. The recent TASK meta-GGA density functional [Phys. Rev. Research, 1, 033082 (2019)] is constructed with an enhanced nonlocality in the generalized Kohn-Sham scheme, and therefore harbors great opportunities for band gap prediction. Although this approximation was found to yield excellent band gaps of bulk solids, this accuracy cannot be straightforwardly transferred to low-dimensional materials. The reduced screening of these materials results in larger band gaps compared to their bulk counterparts, as an additional barrier to overcome. In this work we demonstrate how the alteration of exact physical constraints in this functional affects the band gaps of monolayers and nanoribbons, and present accurate band gaps competing with the HSE06 approximation. In order to achieve this goal, we have modified the TASK functional (a) by changing the tight upper-bound for one or two-electron systems (h 0 X ) from 1.174 to 1.29 (b) by changing the limit of interpolation function f X (α → ∞)of the TASK functional that interpolates the exchange enhancement factor F X (s, α) from α = 0 to 1. The resulting modified TASK (mTASK) was tested for various materials from 3D to 2D to 1D (nanoribbons), and was compared with the results of the higher-level hybrid functional HSE06or with the G 0 W 0 approximation within many-body perturbation theory. We find that mTASK greatly improves the band gaps and band structures of 2D and 1D systems, without significantly affecting the accuracy of the original TASK for the bulk 3D materials, when compared to the PBE-GGA and SCAN meta-GGA. We further demonstrate the applicability of mTASK by assessing the band structures of TMD nanoribbons with respect to various bending curvatures.

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Many-body effects on the electronic and optical properties of strained semiconducting carbon nanotubes

Cited by 13 publications

References 38 publications

Electronic and optical gap renormalization in carbon nanotubes near a metallic surface

Electronic and optical gap renormalization in carbon nanotubes near a metallic surface

Carbon Nanotubes for Mechanical Sensor Applications

Opening band gaps of low-dimensional materials at the meta-GGA level of density functional approximations

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