Signatures of Coherent Phonon Transport in Ultralow Thermal Conductivity Two-Dimensional Ruddlesden–Popper Phase Perovskites

ACS Nano ◽  
2021 ◽  
Author(s):  
Alexander D. Christodoulides ◽  
Peijun Guo ◽  
Lingyun Dai ◽  
Justin M. Hoffman ◽  
Xiaotong Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Phonon Transport ◽  
Coherent Phonon ◽  
Two Dimensional

Theoretical Thermal Conductivity of Periodic Two-Dimensional Nanocomposites

2003 ◽  
Vol 793 ◽  
Author(s):  
Ronggui Yang ◽  
Gang Chen
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
High Efficiency ◽  
Transport Model ◽  
Cell Interaction ◽  
Phonon Transport ◽  
Two Dimensional ◽  
Boltzmann Transport ◽  
Volumetric Fraction ◽  
Strong Function

ABSTRACTA phonon Boltzmann transport model is established to study the lattice thermal conductivity of nanocomposites with nanowires embedded in a host semiconductor material. Special attention has been paid to cell-cell interaction using periodic boundary conditions. The simulation shows that the temperature profiles in nanocomposites are very different from those in conventional composites, due to ballistic phonon transport at nanoscale. The thermal conductivity of periodic 2-D nanocomposites is a strong function of the size of the embedded wires and the volumetric fraction of the constituent materials. At constant volumetric fraction the smaller the wire diameter, the smaller is the thermal conductivity of periodic two-dimensional nanocomposites. For fixed silicon wire dimension, the lower the atomic percentage of germanium, the lower the thermal conductivity of the nanocomposites. The results of this study can be used to direct the development of high efficiency thermoelectric materials.

Disorder limits the coherent phonon transport in two-dimensional phononic crystal structures

Nanoscale ◽  
2019 ◽  
Vol 11 (24) ◽  
pp. 11839-11846 ◽  
Author(s):  
Shiqian Hu ◽  
Zhongwei Zhang ◽  
Pengfei Jiang ◽  
Weijun Ren ◽  
Cuiqian Yu ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Phononic Crystal ◽  
Phonon Transport ◽  
Coherent Phonon ◽  
Two Dimensional ◽  
Coherent Phonons

κCNPnC showed a non-monotonic dependence on porosity, and the localization of coherent phonons induced a substantial suppression of κD-C3N.

scholarly journals Uniform Strain-Dependent Thermal Conductivity of Pentagonal and Hexagonal Silicene

2021 ◽  
Vol 8 ◽  
Author(s):  
Huake Liu ◽  
Guangzhao Qin ◽  
Ming Hu
Keyword(s):  
Thermal Conductivity ◽  
Detailed Analysis ◽  
Group Velocity ◽  
Phonon Transport ◽  
Two Dimensional ◽  
Transport Behavior ◽  
Out Of Plane ◽  
The Difference ◽  
Silicon Based ◽  
Strain Dependent

Two-dimensional (2D) pentagonal monolayer structures have shown promising characteristics and fascinating physical and chemical properties. The disparate strain-dependent thermal conductivity of two-dimensional penta-structures was reported, but the difference between the silicon-based pentagonal and hexagonal structures is barely researched. In this work, based on first-principles calculations, we studied the strain-modulated phonon transport behavior of two 2D pentagonal (penta-SiH and bilayer penta-Si) and one hexagonal silicene structures (H-silicene), of which the penta-SiH and H-silicene mean the structures are hydrogenated for the purpose of thermodynamical stability. We found that the silicon-based pentagonal structure also presented a different strain-dependent thermal conductivity from other pentagonal materials, such as penta-graphene, penta-SiC, or penta-SiN. Moreover, even with the similar strain-dependent thermal transport behavior in penta-SiH and bilayer penta-silicene, we find that the governing mechanism is still different. For both pentagonal silicene structures, the thermal conductivity presents a large improvement at first as the tensile strain increases from 0 to 10% and then stabilizes with a strain larger than 10%. A detailed analysis shows that the in-plane modes contributed the most part to the group velocity enhancement under strains in penta-SiH which is opposite from the bilayer penta-graphene, although the phonon group velocity and phonon lifetime of both structures increase with applied strain. On the other hand, a similarity was found in pentagonal silicene and hexagonal silicene despite the differences in geometry structures. Furthermore, based on the detailed analysis between the pentagonal (penta-SiH) and hexagonal silicene structures (H-silicene), the difference in out-of-plane phonon scattering cannot be ignored: different major scattering channels of the out-of-plane flexural modes result in different thermal conductivity sensitivity to strains, and the disparity in anharmonicity leads to different thermal conductivity under no strain.

scholarly journals Coherent phonon transport in short-period two-dimensional superlattices of graphene and boron nitride

2016 ◽  
Vol 93 (12) ◽  
Author(s):  
Carlos da Silva ◽  
Fernan Saiz ◽  
David A. Romero ◽  
Cristina H. Amon
Keyword(s):  
Boron Nitride ◽  
Phonon Transport ◽  
Coherent Phonon ◽  
Two Dimensional ◽  
Short Period

Two-dimensional bucking structure induces the ultra-low thermal conductivity: A comparative study of the group GaX (X = N, P, As)

2022 ◽  
Author(s):  
Chen Shen ◽  
Niloofar Hadaeghi ◽  
Harish K. Singh ◽  
Teng Long ◽  
Ling Fan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Gallium Nitride ◽  
Comparative Study ◽  
Transport Properties ◽  
Honeycomb Structure ◽  
Phonon Transport ◽  
Two Dimensional ◽  
Low Thermal Conductivity

With the successful synthesis of the two-dimensional (2D) gallium nitride (GaN) in a planar honeycomb structure, the phonon transport properties of 2D GaN have been reported. However, it still remains...

Phonon transport in the ground state of two-dimensional silicon and germanium

RSC Advances ◽  
2016 ◽  
Vol 6 (74) ◽  
pp. 69956-69965 ◽  
Author(s):  
Yang Han ◽  
Jinming Dong ◽  
Guangzhao Qin ◽  
Ming Hu
Keyword(s):  
Thermal Conductivity ◽  
Ground State ◽  
Phonon Transport ◽  
Two Dimensional ◽  
Silicon And Germanium

Lower thermal conductivity and intrinsic electronic bandgap make large honeycomb dumbbell silicene/germanene prospective in future thermoelectrics.

Influence of heat source size and film thickness on phonon transport in a two-dimensional thin film

2014 ◽  
Vol 39 (2) ◽  
Author(s):  
Haider Ali ◽  
Bekir S. Yilbas
Keyword(s):  
Thin Film ◽  
Thermal Conductivity ◽  
Heat Source ◽  
Film Thickness ◽  
Thermal Resistance ◽  
Effective Thermal Conductivity ◽  
Phonon Transport ◽  
Source Size ◽  
Two Dimensional ◽  
Ballistic Phonons

Abstract.Phonon transport in a two-dimensional thin silicon film is considered and the effect of heat source size and the film thickness on the transport characteristics is examined. Frequency dependent Boltzmann equation is incorporated in the analysis to account for the contribution of the ballistic phonons to the energy transport. Equivalent equilibrium temperature is introduced to assess the thermal resistance during the phonon transport in the film. The numerical scheme with the appropriate boundary conditions is used to predict the transport properties, including the effective thermal conductivity, of the thin film. It is found that the heat source size and the film thickness influence the thermal resistance of the film almost equally. The ballistic phonons reduce the film thermal resistance while suppressing the effective thermal conductivity in the thin film.

scholarly journals Decoupling electron and phonon transport in single-nanowire hybrid materials for high-performance thermoelectrics

2021 ◽  
Vol 7 (20) ◽  
pp. eabe6000
Author(s):  
Lin Yang ◽  
Madeleine P. Gordon ◽  
Akanksha K. Menon ◽  
Alexandra Bruefach ◽  
Kyle Haas ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Transport ◽  
Electrical Transport ◽  
High Performance ◽  
Figure Of Merit ◽  
Phonon Transport ◽  
Core Shell ◽  
Nanowire Diameter ◽  
High Performing ◽  
Polycrystalline Thin Films

Organic-inorganic hybrids have recently emerged as a class of high-performing thermoelectric materials that are lightweight and mechanically flexible. However, the fundamental electrical and thermal transport in these materials has remained elusive due to the heterogeneity of bulk, polycrystalline, thin films reported thus far. Here, we systematically investigate a model hybrid comprising a single core/shell nanowire of Te-PEDOT:PSS. We show that as the nanowire diameter is reduced, the electrical conductivity increases and the thermal conductivity decreases, while the Seebeck coefficient remains nearly constant—this collectively results in a figure of merit, ZT, of 0.54 at 400 K. The origin of the decoupling of charge and heat transport lies in the fact that electrical transport occurs through the organic shell, while thermal transport is driven by the inorganic core. This study establishes design principles for high-performing thermoelectrics that leverage the unique interactions occurring at the interfaces of hybrid nanowires.

Magnetic and phonon transport properties of two-dimensional room-temperature ferromagnet VSe2

2021 ◽  
Author(s):  
Haohao Sheng ◽  
Haoxiang Long ◽  
Guanzhen Zou ◽  
Dongmei Bai ◽  
Junting Zhang ◽  
...  
Keyword(s):  
Transport Properties ◽  
Room Temperature ◽  
Phonon Transport ◽  
Two Dimensional
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