Electrical Transport Measured in Atomic Carbon Chains

Cretu, Ovidiu; Botello-Méndez, Andrés R.; Janowska, Izabela; Pham‐Huu, Cuong; Charlier, Jean‐Christophe; Banhart, Florian

doi:10.1021/nl4018918

Cited by 215 publications

(232 citation statements)

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“…CAWs, formed by sp-hybridized carbon atoms, are revealing a great potential in terms of electronic, optical and mechanical properties, as recently shown by experimental observations and theoretical predictions [2][3][4][5][6][7]. In the model CAW, a strong structure-property relationship, originating from electron conjugation effects, leads to metallic character of cumulene (i.e.…”

Section: Introductionmentioning

confidence: 99%

Carbon-atom wires produced by nanosecond pulsed laser deposition in a background gas

Casari

Giannuzzi

Russo

2016

Carbon

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Wires of sp-hybridized carbon atoms are attracting interest for both fundamental aspects of carbon science and for their appealing functional properties. The synthesis by physical vapor deposition has been reported to provide sp-rich carbon films but still needs to be further developed and understood in detail. Here the synthesis of carbon-atom wires (CAWs) has been achieved by nanosecond pulsed laser deposition (PLD) expoliting the strong out-of-equilibrium conditions occurring when the ablation plasma is confined in a background gas. Surface Enhnaced Raman scattering (SERS) spectra of deposited films indicates that CAWs are mixed with a mainly sp 2 amorphous carbon in a

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Section: Introductionmentioning

confidence: 99%

Carbon-atom wires produced by nanosecond pulsed laser deposition in a background gas

Casari

Giannuzzi

Russo

2016

Carbon

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“…We choose Be for this proof-ofconcept study as it possesses a bulk lattice parameter commensurate with armchair CNTs, suggesting that effects of artificial mismatch strain will be small. Evidently, phonon lifetimes as well as transport properties of low dimensional carbon materials can change under strain [28,29], however the viability of the decay mechanism demonstrated in the following is not critically sensitive to such details.Phonon dispersion of this combined Be@CNT system, excitation of the phonon modes due to the electron-phonon coupling and the corresponding linewidths 1/τ ν,q are presented on the Fig 2. In agreement with previous calculations [9,25], the electronphonon coupling is most pronounced for optical modes at the points corresponding to Γ and K of graphene BZ. This does not change significantly upon Be encapsulation.…”

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confidence: 98%

Encapsulated nanowires: Boosting electronic transport in carbon nanotubes

et al. 2017

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The electrical conductivity of metallic carbon nanotubes (CNTs) quickly saturates with respect to bias voltage due to scattering from a large population of optical phonons. Decay of these dominant scatterers in pristine CNTs is too slow to offset an increased generation rate at high voltage bias. We demonstrate from first principles that encapsulation of 1D atomic chains within a single-walled CNT can enhance decay of "hot" phonons by providing additional channels for thermalisation. Pacification of the phonon population growth reduces electrical resistivity of metallic CNTs by 51% for an example system with encapsulated beryllium.Carbon Nanotubes (CNTs) are the most promising candidates for nanoelectronics applications due to their excellent electrical conductivity [1][2][3]. With these properties applied in integrated circuits and in the field effect transistors' gate electrodes metallic CNTs lead the minituarisation race at the nanoscale [4]. However experimental and theoretical studies show that electronic transport in metallic CNTs undergoes a dramatic decrease beyond a bias of ≈ 0.2 eV due to scattering of conduction electrons from a population of high frequency phonons [5][6][7][8]. Under bias voltage, the process of electron scattering excites new phonons into this population an order of magnitude faster than their decay via thermalisation [9]. This dominance of excitation over deexcitation results in a growing population of athermal "hot" phonons and consequently a non-equilibrium phonon distribution [10,11]. Under such conditions, these hot phonons constitute the dominant source of electron scattering, and hence resistivity, in metallic CNTs. A mechanism for increasing the rate of phonon thermalisation will therefore enhance the electrical performance of CNTs.The process of phonon deexcitation involves anharmonic phonon-phonon scattering, hence its rate is dependent on the number of available channels for phonon decay. Previously, several possible solutions for introduction of additional thermalisation channels were suggested that considered a supporting substrate or isotopic disorder [12][13][14].In this letter we show that reduction of the hot phonon population under bias is readily achievable via encapsulation of 1D nanowires in single-walled CNTs (SWCNT). We consider phonon-phonon relaxation from first principles and demonstrate that an encapsulated one-dimensional crystal creates additional channels for hot phonon thermalisation, increasing the decay rate. This results in a significant improvement of the voltage-current ratio at high bias voltage. Transport is studied by solving the set of parameter-free Boltzmann transport equations (BTE) for coupled dynamics of electrons and phonons, whilst all relevant scattering rates are calculated ab initio with densityfunctional perturbational theory (DFPT). This route to enhanced transport is attractive due to increasingly well-established methods for growth of 1D crystals inside CNTs [15][16][17][18][19] and assembly of nanowires into integrated devices [...

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“…22 ) Specifically, stretching increases the bond length alternation (BLA, defined as the difference between the long and short bonds) and the band gap. Although the effect of strain on the band gap is wellknown in semiconductors, the present case is very abnormal-see discussion in Supplementary Information (SI)-both in the sign of the dependence and the greater amplitude (∂Eg/∂ = 12.3-29.7 eV, see Fig.…”

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confidence: 99%

Mechanically Induced Metal–Insulator Transition in Carbyne

2014

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First-principles calculations for carbyne under strain predict that the Peierls transition from symmetric cumulene to broken-symmetry polyyne structure is enhanced as the material is stretched. Interpretation within a simple and instructive analytical model suggests that this behavior is valid for arbitrary 1D metals. Further, numerical calculations of the anharmonic quantum vibrational structure of carbyne show that zero-point atomic vibrations alone eliminate the Peierls distortion in a mechanically free chain, preserving the cumulene symmetry. The emergence and increase of Peierls dimerization under tension then implies a qualitative transition between the two forms, which our computations place around 3% strain. Thus, zero-point vibrations and mechanical strain jointly produce a change in symmetry resulting in the transition from metallic to insulating state. In any practical realization, it is important that the effect is also chemically modulated by the choice of terminating groups. Our findings are promising for applications such as electromechanical switching and band gap tuning via strain, and besides carbyne itself, they directly extend to numerous other systems that show Peierls distortion.Carbyne-the linear allotrope of carbon-is perhaps one of the most unusual materials due to its ultimate one-atom thinness. Although carbyne is elusively hard to prepare and has been perceived as an exotic or even completely fictitious material, the development of methods to synthesize carbon chains proceeds at a steady rate, with input from both experiments and theory. 1-7 Among the most notable recent achievements, chains with length of up to 44 atoms 8 and such complex molecular machines as carbyne-based rotaxanes 9,10 have been synthesized. This progress is driven by carbyne's attractive physical properties such as unusual electrical transport 11,12 and intriguing mechanics, 13 or its large specific area. 14 Accordingly, a better theoretical understanding of this material is becoming more and more relevant. 13 It has long ago been established by the quantum chemistry community 15 that carbyne undergoes the Peierls transition [16][17][18][19] that converts it from the cumulene (=C=C=) n to the polyyne (-C≡C-) n form. Later it has been suggested that the zero-point vibrations (ZPV) may substantially affect the Peierls instability 20 and even completely eliminate the distortion in carbyne. 21 As the symmetric and broken-symmetry forms have very distinct electronic properties (metallic and insulating, respectively), this issue becomes crucial from both the fundamental physicochemical perspective and for applications in 1D conducting systems.A whole new dimension is added to the situation by the unusual effects of stretching on carbyne that we have recently found through first-principles calculations 13 (also observed experimentally after the present study had been completed. 22 ) Specifically, stretching increases the bond length alternation (BLA, defined as the difference between the long and short bonds) and the ba...

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Electrical Transport Measured in Atomic Carbon Chains

Cited by 215 publications

References 46 publications

Carbon-atom wires produced by nanosecond pulsed laser deposition in a background gas

Carbon-atom wires produced by nanosecond pulsed laser deposition in a background gas

Encapsulated nanowires: Boosting electronic transport in carbon nanotubes

Mechanically Induced Metal–Insulator Transition in Carbyne

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