Designing chemical analogs to PbTe with intrinsic high band degeneracy and low lattice thermal conductivity

He, Jiangang; Xia, Yi; Naghavi, S. Shahab; Ozoliņš, Vidvuds; Wolverton, Christopher

doi:10.1038/s41467-019-08542-1

Cited by 63 publications

(57 citation statements)

References 59 publications

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“…Because the Seebeck coefficient, electrical conductivity and electronic thermal conductivity are related to the electronic structure and carrier concentration, it is difficult to adjust and control a certain parameter alone to improve the thermoelectric properties of the material. In recent years, the efforts to enhance the ZT value mainly focus on improving the power factor through energy band engineering and reducing the thermal conductivity through nanometre or superlattice [ 1 – 6 ]. Both theoretical and experimental research shows that these methods can effectively improve ZT value, but it is difficult to be applied for the difficulty in preparation.…”

Section: Introductionmentioning

confidence: 99%

“…material. In recent years, the efforts to enhance the ZT value mainly focus on improving the power factor through energy band engineering and reducing the thermal conductivity through nanometre or superlattice [1][2][3][4][5][6]. Both theoretical and experimental research shows that these methods can effectively improve ZT value, but it is difficult to be applied for the difficulty in preparation.…”

Section: Introductionmentioning

confidence: 99%

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Thermoelectric performances for both p- and n-type GeSe

et al. 2021

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In this paper, the thermoelectric properties of p-type and n-type GeSe are studied systematically by using first principles and Boltzmann transport theory. The calculation includes electronic structure, electron relaxation time, lattice thermal conductivity and thermoelectric transport properties. The results show that GeSe is an indirect band gap semiconductor with band gap 1.34 eV. Though p-type GeSe has a high density of states near Fermi level, the electronic conductivity is relative low because there is no carrier transport pathway along the a -axis direction. For n-type GeSe, a charge density channel is formed near conduction band minimum, which improves the electrical conductivity of n-type GeSe along the a -axis direction. At 700 K, the optimal ZT value reaches 2.5 at 4 × 10 19 cm −3 for n-type GeSe, while that is 0.6 at 1 × 10 20 cm −3 for p-type GeSe. The results show n-type GeSe has better thermoelectric properties than p-type GeSe, indicating that n-type GeSe is a promising thermoelectric material in middle temperature.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermoelectric performances for both p- and n-type GeSe

et al. 2021

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“…[ 8–11 ] For a given carrier concentration, a large carrier effective mass ( m *) contributes to a large S , and the m * is proportional to the band effective mass ( m b *) according to m * = N V 2/3 m b *, where N V refers to the band degeneracy. [ 10,12 ] A large m b *, however, will reduce the carrier mobility μ since

μ \propto 1 / m^{*} {_{b}}^{2}

(2D systems). [ 13–16 ] Hence, to optimize S 2 σ, it is important to attain high N V and moderate m b * simultaneously.…”

Section: Introductionmentioning

confidence: 99%

High ZT 2D Thermoelectrics by Design: Strong Interlayer Vibration and Complete Band‐Extrema Alignment

Zhang

Liu

Tao

et al. 2020

Adv Funct Materials

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The discovery of a record high figure of merit (ZT) of ≈2.6 associated with bulk SnSe has stimulated considerable enthusiasm in searching for 2D systems with similar high ZT. However, previously reported 2D thermoelectric (TE) materials generally possess very low ZT due to the high lattice thermal conductivity (κ L ) and/or small power factor (PF). Herein, a very high ZT (≈2.08) value associated with atomically thin 2D KAgSe nanosheet is reported, which also exhibits an unprecedented low intrinsic κ L (≈0.03 Wm −1 K −1 at 700 K for trilayer) and fairly large PF. The low κ L mainly stems from the high lattice anharmonicity induced by both the "interfacial shear slip" vibrations and the asymmetric "AgSe pair" vibrations from distorted AgSe 4 tetrahedrons. Meanwhile, the complete band-extrema alignment and coexistence of heavy and light bands result in an optimal Seebeck coefficient and electrical conductivity, thereby a large PF. This work suggests not only an alternative way to acquiring high lattice anharmonicity but also a highly competitive 2D TE candidate for wide applications.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.202001200.devices, recently much attention has been devoted to the development of 2D highefficiency TE materials with controllable thickness. [5][6][7] In general, the TE efficiency is characterized by the dimensionless figure of merit ZT = S 2 σT/(κ L + κ e ), where S, σ, T, κ L , and κ e are Seebeck coefficient, electrical conductivity, absolute temperature, lattice thermal conductivity and electronic thermal conductivity, respectively. Apparently, the high TE efficiency can be achieved by increasing the power factor (PF = S 2 σ) together with suppressing the sum of thermal conductivity (κ L + κ e ).Currently, the TE efficiency can be improved by two approaches: i) Tuning effective mass to improve the electronic transport and ii) increasing phonon scattering to suppress the lattice thermal transport. [8][9][10][11] For a given carrier concentration, a large carrier effective mass (m*) contributes to a large S, and the m* is proportional to the band effective mass (m b *) according to m* = N V 2/3 m b *, where N V refers to the band degeneracy. [10,12] A large m b *, however, will reduce the carrier mobility μ since m b 1/ * 2 µ ∝ (2D systems). [13][14][15][16] Hence, to optimize S 2 σ, it is important to attain high N V and moderate m b * simultaneously. A high N V can be achieved either by mixing two types of low-symmetric compounds into a reconstructed highly symmetric structure or by alloying/doping to converge different bands in the Brillouin zone. [8,[17][18][19] For electronic bands at the band edge, a moderate m b * can be realized in principle through element doping or strain engineering. [20] However, in practice, many compounds have limited doping capability and are easily damaged by strain; and the crystal symmetry of the reconstructed structure is uncontrollable. Regarding increasing phonon scattering, intro...

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“…In recent years, crystal structure prediction has played an increasingly important role, not only for understanding the ground-state structure of matter, but also for designing materials and drug molecules with desired functionality (Oganov, 2018 ; He et al, 2019 ; Zhao et al, 2019 ; Xie et al, 2020 ). Generally speaking, a ground-state crystal structure prediction method involves three components: a model that generates the interatomic potential energy surface (PES) and forces, a sampling technique for exploring different conformations in the configuration space, and a relaxation procedure to find the local minima on the PES (Podryabinkin et al, 2019 ).…”

Section: Introductionmentioning

confidence: 99%

Crystal Structure Prediction of Binary Alloys via Deep Potential

Wang

Zhang

et al. 2020

Front. Chem.

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Predicting crystal structure has been a challenging problem in physics and materials science for a long time. A reliable energy calculation engine combined with an efficient global search algorithm, such as particle swarm optimization algorithm or genetic algorithm, is needed to conduct crystal structure prediction. In recent years, machine learning-based interatomic potential energy surface models have been proposed, potentially allowing us to perform crystal structure prediction for systems with the accuracy of density functional theory (DFT) and the speed of empirical force fields. In this paper, we employ a previously developed Deep Potential model to predict the intermetallic compound of the aluminum–magnesium system, and find six meta-stable phases with negative or nearly zero formation energy. In particular, Mg12Al8 shows excellent ductility and Mg5Al27 has a high Young's modulus. Based on our benchmark results, we propose a relatively robust structure screening criterion that selects potentially stable structures from the Deep Potential-based convex hull and performs DFT refinement. By using this criterion, the computational cost needed to construct the convex hull with ab initio accuracy can be dramatically reduced.

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Designing chemical analogs to PbTe with intrinsic high band degeneracy and low lattice thermal conductivity

Cited by 63 publications

References 59 publications

Thermoelectric performances for both p- and n-type GeSe

Thermoelectric performances for both p- and n-type GeSe

High ZT 2D Thermoelectrics by Design: Strong Interlayer Vibration and Complete Band‐Extrema Alignment

Crystal Structure Prediction of Binary Alloys via Deep Potential

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