Thermal conductivity ofYBa2Cu3O7−δbelow 1 K: Evidence for normal-carrier transport well belowTc

1988 ◽  
Vol 38 (4) ◽  
pp. 2892-2895 ◽  
Author(s):  
J. L. Cohn ◽  
S. D. Peacor ◽  
C. Uher
Keyword(s):  
Thermal Conductivity ◽  
Carrier Transport ◽  
Normal Carrier

Synergistic optimization of carrier transport and thermal conductivity in Sn-doped Cu2Te

2018 ◽  
Vol 6 (39) ◽  
pp. 18928-18937 ◽  
Author(s):  
Yuchong Qiu ◽  
Ying Liu ◽  
Jinwen Ye ◽  
Jun Li ◽  
Lixian Lian
Keyword(s):  
Thermal Conductivity ◽  
Fermi Level ◽  
Carrier Concentration ◽  
Power Factor ◽  
Carrier Transport ◽  
Lone Pair ◽  
Thermoelectric Performance ◽  
Degenerate Semiconductors ◽  
Lone Pair Electrons

Doping Sn into the Cu2Te lattice can synergistically enhance the power factor and decrease thermal conductivity, leading to remarkably optimized zTs. The lone pair electrons from the 5s orbital of Sn can increase the DOS near the Fermi level of Cu2Te to promote PF and reduce κe by decreasing the carrier concentration. This study explores a scalable strategy to optimize the thermoelectric performance for intrinsically highly degenerate semiconductors.

Sb deficiencies control hole transport and boost the thermoelectric performance of p-type AgSbSe2

2015 ◽  
Vol 3 (40) ◽  
pp. 10415-10421 ◽  
Author(s):  
Satya N. Guin ◽  
Kanishka Biswas
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Carrier Transport ◽  
Hole Transport ◽  
Thermoelectric Performance ◽  
Low Thermal Conductivity ◽  
New Strategy ◽  
P Type

We demonstrate a new strategy to control the carrier transport in AgSbSe2by introducing Sb deficiencies. Enhanced electrical conductivity and ultra-low thermal conductivity resulted a peak ZT value ∼1 at 610 K in Sb deficient AgSbSe2.

scholarly journals Phase Formation Behavior and Thermoelectric Transport Properties of P-Type YbxFe3CoSb12 Prepared by Melt Spinning and Spark Plasma Sintering

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 87 ◽  
Author(s):  
Kyu Hyoung Lee ◽  
Sang Hyun Bae ◽  
Soon-Mok Choi
Keyword(s):  
Thermal Conductivity ◽  
Power Factor ◽  
Melt Spinning ◽  
Carrier Transport ◽  
Phonon Scattering ◽  
Submicron Scale ◽  
Formation Behavior ◽  
Thermoelectric Transport Properties ◽  
Spinning Process ◽  
P Type

Formation of multiple phases is considered an effective approach for enhancing the performance of thermoelectric materials since it can reduce the thermal conductivity and improve the power factor. Herein, we report the in-situ generation of a submicron-scale (~500 nm) heterograin structure in p-type Yb-filled (Fe,Co)4Sb12 skutterudites during the melt spinning process. Mixed grains of YbxFe3−yCo1+ySb12 and YbzFe3+yCo1−ySb12 were formed in melt spun ribbons due to uneven distribution of cations. By the formation of interfaces between two different grains, the power factor was enhanced due to the formation of an energy barrier for carrier transport, and simultaneously the lattice thermal conductivity was reduced due to the intensified boundary phonon scattering. A high thermoelectric figure of merit zT of 0.66 was obtained at 700 K.

Recent Developments in Bulk Thermoelectric Materials

MRS Bulletin ◽  
2006 ◽  
Vol 31 (3) ◽  
pp. 199-205 ◽  
Author(s):  
George S. Nolas ◽  
Joe Poon ◽  
Mercouri Kanatzidis
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
Carrier Transport ◽  
Heusler Alloys ◽  
Low Thermal Conductivity ◽  
Recent Developments

AbstractGood thermoelectric materials possess low thermal conductivity while maximizing electric carrier transport. This article looks at various classes of materials to understand their behavior and determine methods to modify or “tune” them to optimize their thermoelectric properties. Whether it is the use of “rattlers” in cage structures such as skutterudites, or mixed-lattice atoms such as the complex half-Heusler alloys, the ability to manipulate the thermal conductivity of a material is essential in optimizing its properties for thermoelectric applications.

Thermal Conductivity and Phonon Transport Properties of Silicon Using Perturbation Theory and the Environment-Dependent Interatomic Potential

2009 ◽  
Author(s):  
Jose´ A. Pascual-Gutie´rrez ◽  
Jayathi Y. Murthy ◽  
Raymond Viskanta
Keyword(s):  
Thermal Conductivity ◽  
Perturbation Theory ◽  
Carrier Transport ◽  
Interatomic Potential ◽  
Relaxation Times ◽  
Momentum Conservation ◽  
Phonon Transport ◽  
Boltzmann Transport ◽  
Bulk Silicon ◽  
Energy And Momentum

Perturbation theory is used to compute the strength of three-phonon and isotope scattering mechanisms in silicon using the Environment-Dependent Interatomic Potential (EDIP) without resorting to any parameter-fitting. A detailed methodology to accurately find three-phonon processes satisfying energy- and momentum-conservation rules is described. Bulk silicon thermal conductivity values are computed across a range of temperatures and shown to match experimental data well. It is found that about two-thirds of the heat transport in bulk silicon may be attributed to transverse acoustic modes. Effective relaxation times and mean free paths are computed in order to provide a more complete picture of the detailed transport mechanisms and for use with carrier transport models based on the Boltzmann transport equation.

Semiconductor Nanostructure Design for Thermoelectric Property Control

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940036 ◽  
Author(s):  
Y. Nakamura ◽  
T. Ishibe ◽  
T. Taniguchi ◽  
T. Terada ◽  
R. Hosoda ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Performance ◽  
Carrier Transport ◽  
Phonon Scattering ◽  
Phonon Transport ◽  
Phonon Confinement ◽  
Semiconductor Nanostructure ◽  
Si Nanocrystals ◽  
Si Films ◽  
Property Control

We present the methodologies for developing high-performance thermoelectric materials using nanostructured interfaces by reviewing our three studies and giving the new aspect of nanostructuring results. (1) Connected Si nanocrystals exhibited ultrasmall thermal conductivity. The drastic thermal conductivity reduction was brought by phonon confinement and phonon scattering. Here, we present discussion about the new aspect for phonon transport: not only nanocrystal size but also shape can contribute to thermal conductivity reduction. (2) Si films including Ge nanocrystals demonstrated that phonon and carrier conductions were independently controlled in the films, where carriers were easily transported through the interfaces between Si and Ge, while phonons could be effectively scattered at the interfaces. (3) Embedded-ZnO nanowire structure demonstrated the simultaneous realization of power factor increase and thermal conductivity reduction. The [Formula: see text] increase was caused by the interface-dominated carrier transport. The nanowire interfaces also worked as phonon scatterers, resulting in the thermal conductivity reduction.

scholarly journals Reduced Bipolar Conduction in Bandgap-Engineered n-Type Cu0.008Bi2(Te,Se)3 by Sulfur Doping

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 337 ◽  
Author(s):  
Weon Ho Shin ◽  
Hyun-Sik Kim ◽  
Se Yun Kim ◽  
Sung-sil Choo ◽  
Seok-won Hong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Temperatures ◽  
Figure Of Merit ◽  
Carrier Transport ◽  
Lattice Thermal Conductivity ◽  
Total Thermal Conductivity ◽  
Seebeck Coefficients ◽  
Bipolar Conduction ◽  
Additional Point ◽  
Carrier Transport Properties

Significant bipolar conduction of the carriers in Bi2Te3-based alloys occurs at high temperatures due to their narrow bandgaps. Therefore, at high temperatures, their Seebeck coefficients decrease, the bipolar thermal conductivities rapidly increase, and the thermoelectric figure of merit, zT, rapidly decreases. In this study, band modification of n-type Cu0.008Bi2(Te,Se)3 alloys by sulfur (S) doping, which could widen the bandgap, is investigated regarding carrier transport properties and bipolar thermal conductivity. The increase in bandgap by S doping is demonstrated by the Goldsmid–Sharp estimation. The bipolar conduction reduction is shown in the carrier transport characteristics and thermal conductivity. In addition, S doping induces an additional point-defect scattering of phonons, which decreases the lattice thermal conductivity. Thus, the total thermal conductivity of the S-doped sample is reduced. Despite the reduced power factor due to the unfavorable change in the conduction band, zT at high temperatures is increased by S doping with simultaneous reductions in bipolar and lattice thermal conductivity.

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