Critical analysis of lattice thermal conductivity of half-Heusler alloys using variations of Callaway model

2015 ◽  
Vol 117 (3) ◽  
pp. 035706 ◽  
Author(s):  
Alex Petersen ◽  
S. Bhattacharya ◽  
T. M. Tritt ◽  
S. J. Poon
Keyword(s):  
Thermal Conductivity ◽  
Critical Analysis ◽  
Lattice Thermal Conductivity ◽  
Heusler Alloys ◽  
Callaway Model

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.

scholarly journals Silver vacancy concentration engineering leading to the ultralow lattice thermal conductivity and improved thermoelectric performance of Ag1-xInTe2

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yaqiong Zhong ◽  
Yong Luo ◽  
Xie Li ◽  
Jiaolin Cui
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Point Defects ◽  
Lattice Thermal Conductivity ◽  
Vacancy Concentration ◽  
Antisite Defect ◽  
Thermoelectric Performance ◽  
Callaway Model

AbstractAgInTe2 compound has not received enough recognition in thermoelectrics, possibly due to the fact that the presence of Te vacancy (VTe) and antisite defect of In at Ag site (InAg) degrades its electrical conductivity. In this work, we prepared the Ag1-xInTe2 compounds with substoichiometric amounts of Ag and observed an ultralow lattice thermal conductivity (κL = 0.1 Wm−1K−1) for the sample at x = 0.15 and 814 K. This leads to more than 2-fold enhancement in the ZT value (ZT = 0.62) compared to the pristine AgInTe2. In addition, we have traced the origin of the untralow κL using the Callaway model. The results attained in this work suggest that the engineering of the silver vacancy (VAg) concentration is still an effective way to manipulate the thermoelectric performance of AgInTe2, realized by the increased point defects and modified crystal structure distortion as the VAg concentration increases.

Thermal Expansion and Isotopic Composition Effects on Lattice Thermal Conductivities of Crystalline Silicon

2006 ◽  
Author(s):  
Yunfei Chen ◽  
Guodong Wang ◽  
Deyu Li ◽  
Jennifer R. Lukes
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Md Simulation ◽  
Lattice Thermal Conductivity ◽  
Mass Difference ◽  
Dynamics Simulation ◽  
Temperature Range ◽  
Simulation Results ◽  
Callaway Model ◽  
Thermal Conductivities

Equilibrium molecular dynamics simulation is used to calculate lattice thermal conductivities of crystal silicon in the temperature range from 400K to 1600K. Simulation results confirmed that thermal expansion, which resulted in the increase of the lattice parameter, caused the decrease of the lattice thermal conductivity. The simulated results proved that thermal expansion imposed another type resistance on phonon transport in crystal materials. Isotopic and vacancy effects on lattice thermal conductivity are also investigated and compared with the prediction from the modified Debye Callaway model. It is demonstrated in the MD simulation results that the isotopic effect on lattice thermal conductivity is little in the temperature range from 400K to 1600K for isotopic concentration below 1%, which implies the isotopic scattering on phonon due to mass difference can be neglected over the room temperature. The remove of atoms from the crystal matrix caused mass difference and elastic strain between the void and the neighbor atoms, which resulted in vacancy scattering on phonons. Simulation results demonstrated this mechanism is stronger than that caused by isotopic scattering on phonons due to mass difference. A good agreement is obtained between the MD simulation results of silicon crystal with vacancy defects and the data predicted from the modified Debye Callaway model. This conclusion is helpful to demonstrate the validity of Klemens' Rayleigh model for impurity scattering on phonons.

scholarly journals Lattice thermal conductivity ofTixZryHf1−x−yNiSnhalf-Heusler alloys calculated from first principles: Key role of nature of phonon modes

2017 ◽  
Vol 95 (4) ◽  
Author(s):  
Simen N. H. Eliassen ◽  
Ankita Katre ◽  
Georg K. H. Madsen ◽  
Clas Persson ◽  
Ole Martin Løvvik ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
First Principles ◽  
Lattice Thermal Conductivity ◽  
Heusler Alloys ◽  
Phonon Modes

PHONON HEAT CONDUCTIVITY OF InSb AND CdS

2011 ◽  
Vol 25 (10) ◽  
pp. 1409-1418 ◽  
Author(s):  
M. ATAULLAH ANSARI ◽  
VINOD ASHOKAN ◽  
B. D. INDU
Keyword(s):  
Thermal Conductivity ◽  
Heat Conductivity ◽  
Lattice Thermal Conductivity ◽  
Relaxation Times ◽  
Temperature Range ◽  
Callaway Model ◽  
Theory And Experiments ◽  
Good Agreement

The lattice thermal conductivity of InSb and CdS has been analyzed on the basis of the most acquiescent Callaway model in the temperature range 2–300.779 K and 2.296–283.565 K. To reinvigorate the effects of phonon anharmonicities, more rigorous expressions for the phonon–phonon interactions, resonance, impurity and interference scattering relaxation times have been introduced to theoretically justify the experimentally observed results. A fairly good agreement between theory and experiments has been presented.

Overview of Various Strategies and Promising New Bulk Materials for Potential Thermoelectric Applications

2001 ◽  
Vol 691 ◽  
Author(s):  
Terry M. Tritt
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Material ◽  
Lattice Thermal Conductivity ◽  
Heusler Alloys ◽  
Material Research ◽  
Research Groups ◽  
Ceramic Oxides ◽  
Large Power ◽  
Minimum Requirements ◽  
Low Dimensional

ABSTRACTRecently, there has been a renewed interest in thermoelectric material research. There are a number of different systems of potential thermoelectric (TE) materials that are under investigation by various research groups. Some of these research efforts focus on minimizing lattice thermal conductivity while other efforts focus on materials that exhibit large power factors. An overview of some of the requirements and strategies for the investigation and optimization of a new system of materials for potential thermoelectric applications will be discussed. Some of the newer concepts such as low-dimensional systems and Slack's phononglass, electron-crystal concept will be discussed. Current strategies for minimizing lattice thermal conductivity and also minimum requirements for thermopower will be presented. The emphasis of this paper will be to identify some of the more recent promising bulk materials and discuss the challenges and issues related to each. This paper is targeted more at “newcomers” to the field and does not discuss some of the very interesting results that are being reported in the thin film and superlattice materials. Some of the bulk materials which will be discussed include complex chalcogenides (e.g.CsBi4Te6 and pentatellurides such as the Zr1−XHfXTe5 system), half-Heusler alloys (e.g. TiNiSn1−XSbX), ceramic oxides (NaCo4O2), skutterudites (e.g. YbXCo4−XSb12 or EuXCo4−XSb12) and clathrates (e.g. Sr8Ga16Ge30). Each of these systems is distinctly different yet each exhibits some prospect as a potential thermoelectric material. Results will be presented and discussed on each system of materials.

Reductions in the Lattice Thermal Conductivity of Ball-milled and Shock compacted TiNiSn1−XSbX Half-Heusler alloys

2001 ◽  
Vol 691 ◽  
Author(s):  
S. Bhattacharya ◽  
Y. Xia ◽  
V. Ponnambalam ◽  
S.J. Poon ◽  
N. Thadani ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Heusler Alloys ◽  
Lattice Contribution ◽  
Grain Sizes ◽  
Shock Compaction ◽  
High Figure

ABSTRACTHalf-Heusler alloys are currently being investigated for their potential as thermoelectric materials [1], [2]. They exhibit high negative thermopower (40-250μV/K) and favorable electrical resistivity (0.1-8mW•cm) at room temperature. Attractive power factors (α2σT) of about (0.2-1.0W/m•K) at room temperature and about 4W/m•K at 600K [3] have been reported in these materials. But in order to achieve a high figure-of-merit in the half-Heusler alloys, the relatively high thermal conductivity in these materials (∼ 10 W/m•K) must be reduced. The thermal conductivity in these materials is composed of mainly a lattice contribution, compared to a very small electronic component. The challenge is to reduce the relatively high lattice thermal conductivity in these materials. Reported in this paper is a significant reduction of lattice thermal conductivity (∼1.5 - 3.5W/m•K) in some Ti-based half-Heusler alloys. Samples have been prepared by ball milling and followed by shock-compaction that has resulted into reduced grain sizes in these materials. The effects of the microstructure on the thermal transport properties of the Half-Heusler alloys have been investigated and are presented and discussed herein.

scholarly journals Thermoelectric Transport Properties of n-Type Sb-doped (Hf,Zr,Ti)NiSn Half-Heusler Alloys Prepared by Temperature-Regulated Melt Spinning and Spark Plasma Sintering

2020 ◽  
Vol 10 (14) ◽  
pp. 4963 ◽  
Author(s):  
Ki Wook Bae ◽  
Jeong Yun Hwang ◽  
Sang-il Kim ◽  
Hyung Mo Jeong ◽  
Sunuk Kim ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Spark Plasma Sintering ◽  
Figure Of Merit ◽  
Melt Spinning ◽  
Lattice Thermal Conductivity ◽  
Heusler Alloys ◽  
Thermoelectric Figure ◽  
Plasma Sintering ◽  
Thermoelectric Transport Properties ◽  
Spark Plasma

Herein we report a significantly reduced lattice thermal conductivity of Sb-doped Hf0.35Zr0.35Ti0.3NiSn half-Heusler alloys with sub-micron grains (grain size of ~300 nm). Polycrystalline bulks of Hf0.35Zr0.35Ti0.3NiSn1−xSbx (x = 0.01, 0.02, 0.03) with a complete single half-Heusler phase are prepared using temperature-regulated melt spinning and subsequent spark plasma sintering without a long annealing process. In these submicron-grained bulks, a very low lattice thermal conductivity value of ~2.4 W m−1 K−1 is obtained at 300 K due to the intensified phonon scatterings by highly dense grain boundaries and point-defects (Zr and Ti substituted at Hf-sites). A maximum thermoelectric figure of merit, zT, of 0.5 at 800 K is obtained in Hf0.35Zr0.35Ti0.3NiSn0.99Sb0.01.

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