scholarly journals Soft anharmonic phonons and ultralow thermal conductivity in Mg3(Sb, Bi)2 thermoelectrics

2021 ◽  
Vol 7 (21) ◽  
pp. eabg1449
Author(s):  
Jingxuan Ding ◽  
Tyson Lanigan-Atkins ◽  
Mario Calderón-Cueva ◽  
Arnab Banerjee ◽  
Douglas L. Abernathy ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
First Principles ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Inelastic Neutron ◽  
Phonon Softening ◽  
X Ray ◽  
X Ray Scattering ◽  
Transverse Acoustic ◽  
Scattering Phase

The candidate thermoelectric compounds Mg3Sb2 and Mg3Bi2 show excellent performance near ambient temperature, enabled by an anomalously low lattice thermal conductivity (κl) comparable to those of much heavier PbTe or Bi2Te3. Contrary to common mass-trend expectations, replacing Mg with heavier Ca or Yb yields a threefold increase in κl in CaMg2Sb2 and YbMg2Bi2. Here, we report a comprehensive analysis of phonons in the series AMg2X2 (A = Mg, Ca, and Yb; X = Bi and Sb) based on inelastic neutron/x-ray scattering and first-principles simulations and show that the anomalously low κl of Mg3X2 has inherent phononic origins. We uncover a large phonon softening and flattening of low-energy transverse acoustic phonons in Mg3X2 compared to the ternary analogs and traced to a specific Mg-X bond, which markedly enlarges the scattering phase-space, enabling the threefold tuning in κl. These results provide key insights for manipulating phonon scattering without the traditional reliance on heavy elements.

scholarly journals First-principles predictions of low lattice thermal conductivity and high thermoelectric performance of AZnSb (A = Rb, Cs)

RSC Advances ◽  
2021 ◽  
Vol 11 (25) ◽  
pp. 15486-15496
Author(s):  
Enamul Haque
Keyword(s):  
Thermal Conductivity ◽  
Debye Temperature ◽  
Layered Structure ◽  
First Principles ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Thermoelectric Performance

The layered structure, and presence of heavier elements Rb/Cs and Sb induce high anharmonicity, low Debye temperature, intense phonon scattering, and hence, low lattice thermal conductivity.

scholarly journals First-principles prediction of structural stability and thermoelectric properties of SrGaSnH

RSC Advances ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 3304-3314
Author(s):  
Enamul Haque ◽  
Mizanur Rahaman
Keyword(s):  
Thermal Conductivity ◽  
Structural Stability ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure

Weak anharmonicity: the weak anharmonicity leads to weak phonon scattering in SrGaSnH. Thus, SrGaSnH intrinsically possesses a high lattice thermal conductivity (kl).. Such large κl dramatically reduces the thermoelectric figure of merit.

scholarly journals First-Principles Study on Lattice Dynamics and Thermal Conductivity of Thermoelectric Intermetallics Fe3Al2Si3

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 388
Author(s):  
Naoki Sato ◽  
Yoshiki Takagiwa
Keyword(s):  
Thermal Conductivity ◽  
First Principles ◽  
Thermal Transport ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Microscopic Mechanism ◽  
Practical Applications ◽  
Scattering Rate ◽  
Fine Microstructure ◽  
Thermal Displacements

Thermoelectric materials have been expected as a critical underlying technology for developing an autonomous power generation system driven at near room temperature. For this sake, Fe3Al2Si3 intermetallic compound is a promising candidate, though its high lattice thermal conductivity is a bottleneck toward practical applications. Herein, we have performed the first-principles calculations to clarify the microscopic mechanism of thermal transport and establish effective ways to reduce the lattice thermal conductivity of Fe3Al2Si3. Our calculations show that the lowest-lying optical mode has a significant contribution from Al atom vibration. It should correspond to large thermal displacements Al atoms. However, these behaviors do not directly cause an increase of the 3-phonon scattering rate. The calculated lattice thermal conductivity shows a typical temperature dependence and moderate magnitude. From the calculated thermal conductivity spectrum and cumulative thermal conductivity, we can see that there is much room to reduce the lattice thermal conductivity. We can expect that heavy-element doping on Al site and controlling fine microstructure are effective strategies to decrease the lattice thermal conductivity. This work suggests useful information to manipulate the thermal transport of Fe3Al2Si3, which will make this material closer to practical use.

Lattice Thermal Conductivity Modelling of a Diatomic Nanoscale Material

2020 ◽  
Vol 10 (5) ◽  
pp. 602-609
Author(s):  
Adil H. Awad
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Correction Term ◽  
Nanoscale Material ◽  
New Approach ◽  
Two Samples ◽  
Conductivity Modelling ◽  
Callaway Model

Introduction: A new approach for expressing the lattice thermal conductivity of diatomic nanoscale materials is developed. Methods: The lattice thermal conductivity of two samples of GaAs nanobeam at 4-100K is calculated on the basis of monatomic dispersion relation. Phonons are scattered by nanobeam boundaries, point defects and other phonons via normal and Umklapp processes. Methods: A comparative study of the results of the present analysis and those obtained using Callaway formula is performed. We clearly demonstrate the importance of the utilised scattering mechanisms in lattice thermal conductivity by addressing the separate role of the phonon scattering relaxation rate. The formulas derived from the correction term are also presented, and their difference from Callaway model is evident. Furthermore their percentage contribution is sufficiently small to be neglected in calculating lattice thermal conductivity. Conclusion: Our model is successfully used to correlate the predicted lattice thermal conductivity with that of the experimental observation.

Metal phosphide CuP2 as a promising thermoelectric material: an insight from first-principles study

2021 ◽  
Author(s):  
Un-Gi Jong ◽  
Chol-Hyok Ri ◽  
Chol-Jin Pak ◽  
Chol-Hyok Kim ◽  
Stefaan Cottenier ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Material ◽  
Thermoelectric Materials ◽  
First Principles ◽  
Lattice Thermal Conductivity ◽  
Metal Phosphide ◽  
First Principles Study ◽  
Metal Phosphides ◽  
Large Lattice

In the search for better thermoelectric materials, metal phosphides have not been considered to be viable candidates so far, due to their large lattice thermal conductivity. Here we study thermoelectric...

Thermal conductivity and inelastic X-ray scattering measurements on SiGeSn polycrystalline alloy

2021 ◽  
Vol 60 (SB) ◽  
pp. SBBF11
Author(s):  
Yosuke Shimura ◽  
Kako Iwamoto ◽  
Ryo Yokogawa ◽  
Motohiro Tomita ◽  
Hirokazu Tatsuoka ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
X Ray ◽  
X Ray Scattering ◽  
Polycrystalline Alloy ◽  
Scattering Measurements ◽  
Ray Scattering
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