Design rules for interfacial thermal conductance: Building better bridges

Polanco, Carlos A.; Rastgarkafshgarkolaei, Rouzbeh; Zhang, Jingjie; Le, Nam Q.; Norris, Pamela M.; Ghosh, Avik W.

doi:10.1103/physrevb.95.195303

Cited by 49 publications

(52 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While for the impedance increasing material, when reflected from the second boundary, both the first two waves will exhibit half-wave loss. Therefore, in the long-wave limit, the phonon wave will travel half wavelength closer than the one reflected from the first boundary, leading to destructive interference, and finally promote the thermal transport across the interface which is certainly coincident with simulations [39][40][41]. Since the wavelength is frequency dependent, in other frequency domains, more factors must be considered, such as the thickness of the interfacial medium, so that the constructive or destructive interference between the two waves reflected to the left region occurs.…”

Section: Discussionsupporting

confidence: 57%

Phonon quarters-wave loss

Xiong

Wang

2019

New J. Phys.

View full text Add to dashboard Cite

There has been a growing interest in the phase of phonon, due to the theoretical prediction (Phys. Rev. Lett. 115.11 (2015)) and the experimental observation (Science 359.6379 (2018)) of chiral phonons, which have different phases in different components. While half-wave loss is a well-known concept in optics, in this work, a series of plateaus of quarters-wave loss are first found for the reflected phonon across an interface by using an atomic junction model. These plateaus can be understood by the Smatrix in the system with time-reversal symmetry. If a phonon wave propagates from a low acousticimpedance material (or a low cutoff frequency material) to a higher one in the long-wave limit (or in the high frequency limit), a half-wave loss takes place for the reflected phonon; however, the plateau of half-wave loss for reflected phonon occurs in the whole frequency domain if phonon transfers to a material with a larger spring constant. Besides the half-wave loss, we also observe plateaus of quarterwave (three-quarters-wave) loss in long wave limit when the two leads with identical acoustic impedance are coupled by a weak (strong) coupling in comparison with the optimum thermal coupling. The quarters-wave loss for phonons can be applied to chiral phonon manipulation and other phononics devices.

show abstract

Section: Discussionsupporting

confidence: 57%

Phonon quarters-wave loss

Xiong

Wang

2019

New J. Phys.

View full text Add to dashboard Cite

show abstract

“…Details of the calculations are given in the Supplemental Material, 17 and we note that we have benchmarked our GF algorithms against various previous works in the literature, including those simulating random interatomic mixing at interfaces, as described in our previous works. 62,63 To explore the contribution of coherent phonon transport on the thermal conductance, we simulate SLs with perfect interfaces and SLs with interatomic mixing at the interfaces. Phonon transport is fully coherent for the SLs with perfect interfaces due to the construction of the GF method.…”

Section: Discussion and Modeling: Coherent Vs Incoherent Effectsmentioning

confidence: 99%

Interplay between total thickness and period thickness in the phonon thermal conductivity of superlattices from the nanoscale to the microscale: Coherent versus incoherent phonon transport

et al. 2018

Self Cite

View full text Add to dashboard Cite

We report on the room temperature thermal conductivity of AlAs-GaAs superlattices (SLs), in which we systematically vary the period thickness and total thickness between 2 − 24 nm and 20.1 − 2,160 nm, respectively. The thermal conductivity increases with the SL thickness and plateaus at a thickness around 200 nm, showing a clear transition from a quasi-ballistic to a diffusive phonon transport regime. These results demonstrate the existence of classical size effects in SLs, even at the highest interface density samples. We use harmonic Atomistic Green's function calculations to capture incoherence in phonon transport by averaging the calculated transmission over several purely coherent simulations of independent SL with different random mixing at the AlAs-GaAs interfaces. These simulations demonstrate the significant contribution of incoherent phonon transport through the decrease in the transmission and conductance in the SLs as the number of interfaces increases. In spite of this conductance decrease, our simulations show a quasilinear increase in thermal conductivity with the superlattice thickness. This suggests that the observation of a quasilinear increase in thermal conductivity can have important contributions from incoherent phonon transport. Furthermore, this seemingly linear slope in thermal conductivity vs. SL thickness data may actually be non-linear when extended to a larger number of periods, which is a signature of incoherent effects. Indeed, this trend for superlattices with interatomic mixing at the interfaces could easily be interpreted as linear when the number of periods is small. Our results reveal that the change in thermal conductivity with period thickness is dominated by incoherent (particlelike) phonons, whose properties are not dictated by changes in the AlAs or GaAs phonon dispersion relations. This work demonstrates the importance of studying both period and sample thickness dependencies of thermal conductivity to understand the relative contributions of coherent and incoherent phonon transport in the thermal conductivity in SLs.

show abstract

“…Another approach to enhance h K across interfaces is by altering the vibrational density of states at the interfacial region through engineering mass graded boundaries via intermixing of the species or by insertion of an interfacial film that bridges the vibrational properties of the two solids in contact . In comparison to a sharp and abrupt interface, the compositionally disordered (and mass graded) interfaces can demonstrate enhanced h K through vibrational impedance matching between the two solids along with opening new channels of heat transport via anharmonic interactions.…”

Section: Effect Of Nanostructuring and Surface Functionalizationmentioning

confidence: 99%

A Review of Experimental and Computational Advances in Thermal Boundary Conductance and Nanoscale Thermal Transport across Solid Interfaces

Giri

Hopkins

2019

Adv Funct Materials

182

148

View full text Add to dashboard Cite

Interfacial thermal resistance is the primary impediment to heat flow in materials and devices as characteristic lengths become comparable to the mean‐free paths of the energy carriers. This thermal boundary conductance across solid interfaces at the nanoscale can affect a plethora of applications. The recent experimental and computational advances that have led to significant atomistic insights into the nanoscopic thermal transport mechanisms at interfaces between various types of materials are summarized. The authors focus on discussions of works that have pushed the limits to interfacial heat transfer and drastically increased the understanding of thermal boundary conductance on the atomic and nanometer scales near solid/solid interfaces. Specifically, the role of localized interfacial modes on the energy conversion processes occurring at interfaces is emphasized in this review. The authors also focus on experiments and computational works that have challenged the traditionally used phonon gas models in interpreting the physical mechanisms driving interfacial energy transport. Finally, the authors discuss the future directions and avenues of research that can further the knowledge of heat transfer across systems with broken symmetries.

show abstract

Design rules for interfacial thermal conductance: Building better bridges

Cited by 49 publications

References 39 publications

Phonon quarters-wave loss

Phonon quarters-wave loss

Interplay between total thickness and period thickness in the phonon thermal conductivity of superlattices from the nanoscale to the microscale: Coherent versus incoherent phonon transport

A Review of Experimental and Computational Advances in Thermal Boundary Conductance and Nanoscale Thermal Transport across Solid Interfaces

Contact Info

Product

Resources

About