Phonon transport in atomic chains coupled by thermal contacts: The role of buffer layer

Zhao, Xinbao; Li, Jing; Yeung, T. C. Au; Kam, C. H.; Chen, Qing-Hu; Sun, Chang Q.

doi:10.1063/1.3359708

Cited by 10 publications

(10 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At an average temperature = 320 K we find that TH,ph ≅ 0.22 TH,el at EL = 1 0 . However, according to the microscopic details of the junction, in particular to the shape of the electrodes, a decrease of TH,ph by about an order of magnitude with respect to the case of an ideal geometry is expected 19 . Therefore, we can assume a minimum contribution of phonons to heat transport of TH,ph ≅ 0.02 TH,el .…”

Section: Phonon Contribution To Thermal Conductancementioning

confidence: 99%

See 1 more Smart Citation

Heat transport through atomic contacts

et al. 2017

View full text Add to dashboard Cite

Metallic atomic junctions pose the ultimate limit to the scaling of electrical contacts 1 . They serve as model systems to probe electrical and thermal transport down to the atomic level as well as quantum effects occurring in one-dimensional systems 2 . Charge transport in atomic junctions has been studied intensively in the last two decades 2,3,4,5 . However, heat transport remains poorly characterized because of significant experimental challenges. Specifically the combination of high sensitivity to small heat fluxes and the formation of stable atomic contacts has been a major hurdle for the development of this field. Here we report on the realization of heat transfer measurements through atomic junctions and analyze the thermal conductance of single atomic gold contacts at room temperature. Simultaneous measurements of charge and heat transport reveal the proportionality of electrical and thermal conductance, quantized with the respective conductance quanta 6 . This constitutes an atomic scale verification of the well-known Wiedemann-Franz law 7 . We anticipate that our findings will be a major advance in enabling the investigation of heat transport properties in molecular junctions, with meaningful implications towards the manipulation of heat at the nanoscale. IntroductionHeat transport and dissipation at the nanoscale has spurred research interest as it severely limits scaling of high performance electronic devices and circuits 8 . Atomic quantum point contacts represent an ideal platform to investigating heat transport in which quantum confinement effects cannot be neglected. The development of experimental techniques, such as scanning tunneling microscopy (STM) and mechanically controlled break junction (MCBJ) enabled the formation and manipulation of monoatomic metallic chains 3,4,5 . Using these techniques, charge transport in atomic junctions has been studied intensively 2,3,4,5 , and, more recently, Joule dissipation 9,10 and thermoelectric effects 11,12 have been successfully probed. Recently, heat dissipation was measured in current-carrying single gold-gold contacts by means of STM with an integrated micro thermocouple in the tip 9 . It was shown that heat dissipates symmetrically into the two contacts, confirming that the electron transmission function T(E) of the junction element around the Fermi energy of the metallic contacts governs this phenomenon. Despite these recent steps forward, the properties of heat conduction through atomic junctions still remain to be fully explored.Electrical conductance in atomic junctions is quantized. A single gold atom contact has a conductance equal to the quantum G0 = 2e 2 /h, where e is the electron charge and h Planck's constant. The Landauer approach used to describe charge transport can also be applied to predict heat transport 13 and predicts the validity of the Wiedemann-Franz (WF) law, which states that the thermal conductance GTH and the electrical conductance GEL are proportional to each other,where T is the absolute temperature and the proportio...

show abstract

Section: Phonon Contribution To Thermal Conductancementioning

confidence: 99%

“…Marked deviations from WF law can occur when electrons are physically confined in 1D systems, in which the Fermi-liquid state is replaced by a Tomonaga-Luttinger liquid state 19 . Owing to 1D confinement of electrons, spin-charge separation occurs, enabling scattering mechanisms to affect charge and heat transport independently.…”

Section: Introductionmentioning

confidence: 99%

Heat transport through atomic contacts

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Therefore, the strategies of developing high ZT device are improving the electronic TE efficiency and reducing the lattice thermal conductivity [14]. Currently, most of the efforts are put in to reduce the lattice thermal conductivity by investigation the phonon transport, which can be found in our previous works [11][12][13]. However, more attentions needs to be paid on the electron transport, as the electronic TE efficiency limits the performance of TE device significantly [14].…”

Section: Introductionmentioning

confidence: 99%

Influence of electron scatterings on thermoelectric effect

Yeung

Kam

2012

Journal of Applied Physics

Self Cite

View full text Add to dashboard Cite

In this work, we employed non-equilibrium Green's function to investigate the electron transport properties in the nanowire with the presence of scatterings. The scattering mechanism is modelled by using the concept of Büttiker probe. The effect of electron scattering is analyzed under three conditions: absence of external field; with a bias voltage; and with a finite temperature difference.It is found weak and strong scatterings strength affect the electron transport in different ways. In the case of weak scattering strength, electron trapping increase the electron density, hereafter boost the conductance significantly. Although the increment in conductance would reduce the Seebeck coefficient slightly, the power factor still increases. In the case of strong scattering strength, electron diffraction causes the redistribution of electrons, accumulation of electron at the ends of the wire blocks current flow; hence the conductance is reduced significantly. Although the Seebeck coefficient increases slightly, the power factor still decreases. The power factor is enhanced by 6% − 18%, at the optimum scattering strength.

show abstract

“…The AGF method has also been used to study thermal transport within graphene nanoribbons 13 and in atomic chains. 14 The accuracy of the AGF method can be further increased by deriving the harmonic interatomic force constants (required for the AGF method) from DFT. Such a first-principles approach has been used to study thermal transport in superlattices, 15 across metal-graphene interfaces, 16 and in molecular junctions.…”

mentioning

confidence: 99%

Relative effect of edge versus basal plane functionalization on graphene/polymer interfacial thermal conductance - Role of in-plane phonons

Garg

2017

Applied Physics Letters

View full text Add to dashboard Cite

We compare the effectiveness of functionalization on the edge with that on the basal plane of graphene in enhancing interfacial thermal transport between polyethylene and graphene using an atomistic Green's function method. Harmonic interatomic force constants needed for the method are derived from the density-functional theory to provide a first-principles estimate of thermal conductance comparison. Computations reveal the thermal conductance for the edge functionalization to be 75% higher relative to the basal plane case at 300 K. Polarization specific transmission calculations are used to provide understanding of these differences. Published by AIP Publishing.

show abstract

Phonon transport in atomic chains coupled by thermal contacts: The role of buffer layer

Cited by 10 publications

References 37 publications

Heat transport through atomic contacts

Heat transport through atomic contacts

Influence of electron scatterings on thermoelectric effect

Relative effect of edge versus basal plane functionalization on graphene/polymer interfacial thermal conductance - Role of in-plane phonons

Contact Info

Product

Resources

About