Atomic disordering advances thermoelectric group IV telluride alloys with a multiband transport

Tang, Jing; Yao, Zheng; Wu, Yujie; Lin, Siqi; Xiong, Fen; Li, W.; Chen, Y.; Zhu, Tiejun; Pei, Yanzhong

doi:10.1016/j.mtphys.2020.100247

Cited by 28 publications

(37 citation statements)

References 63 publications

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“…Temperature dependence of b) electrical conductivity, c) Seebeck coeffcient, and f) power factor for GeTe‐based alloys. [ 11,54 ] d) Room‐temperature α as a function of Δ S for GeTe‐based alloys in comparison with literature data. [ 11,27 ] The dashed lines are guides to the eyes.…”

Section: Resultsmentioning

confidence: 99%

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Medium Entropy‐Enabled High Performance Cubic GeTe Thermoelectrics

Zhi

et al. 2021

Advanced Science

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The configurational entropy is an emerging descriptor in the functional materials genome. In thermoelectric materials, the configurational entropy helps tune the delicate trade‐off between carrier mobility and lattice thermal conductivity, as well as the structural phase transition, if any. Taking GeTe as an example, low‐entropy GeTe generally have high carrier mobility and distinguished zT > 2, but the rhombohedral‐cubic phase transition restricts the applications. In contrast, despite cubic structure and ultralow lattice thermal conductivity, the degraded carrier mobility leads to a low zT in high‐entropy GeTe. Herein, medium‐entropy alloying is implemented to suppress the phase transition and achieve the cubic GeTe with ultralow lattice thermal conductivity yet decent carrier mobility. In addition, co‐alloying of (Mn, Pb, Sb, Cd) facilitates multivalence bands convergence and band flattening, thereby yielding good Seebeck coefficients and compensating for decreased carrier mobility. For the first time, a state‐of‐the‐art zT of 2.1 at 873 K and average zTave of 1.3 between 300 and 873 K are attained in cubic phased Ge0.63Mn0.15Pb0.1Sb0.06Cd0.06Te. Moreover, a record‐high Vickers hardness of 270 is attained. These results not only promote GeTe materials for practical applications, but also present a breakthrough in the burgeoning field of entropy engineering.

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Section: Resultsmentioning

confidence: 99%

“…The inset in (d) is the average zT ave values in the measured temperature range. [ 11,40,54 ] c) Room‐temperature κ ph as a function of Δ S for GeTe‐based alloys in comparison with literature data. [ 10,11,55–57 ] The dashed lines are guides to the eyes.…”

Section: Resultsmentioning

confidence: 99%

Medium Entropy‐Enabled High Performance Cubic GeTe Thermoelectrics

Zhi

et al. 2021

Advanced Science

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“…A peak zT of 1.14 was achieved at 723 K and the average zT of ~1 was comparable with other SnSe-based materials. Similarly, Tang et al [252] intensified atomic disordering to restrain L  of SnTebased materials and combined MnTe for increasing the amount of transporting valence band to tune electrical performance. For Sn 1/3 Pb 1/3 Ge 1/3 Te, monotonously decreasing of L  (as low as 0.6 Wm 1 K 1 ) with the increasing of the disorder parameter total  , which expressed the increased entropy restrained phonon transfer, was observed.…”

Section:  mentioning

confidence: 99%

High-entropy ceramics: Present status, challenges, and a look forward

et al. 2021

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High-entropy ceramics (HECs) are solid solutions of inorganic compounds with one or more Wyckoff sites shared by equal or near-equal atomic ratios of multi-principal elements. Although in the infant stage, the emerging of this new family of materials has brought new opportunities for material design and property tailoring. Distinct from metals, the diversity in crystal structure and electronic structure of ceramics provides huge space for properties tuning through band structure engineering and phonon engineering. Aside from strengthening, hardening, and low thermal conductivity that have already been found in high-entropy alloys, new properties like colossal dielectric constant, super ionic conductivity, severe anisotropic thermal expansion coefficient, strong electromagnetic wave absorption, etc., have been discovered in HECs. As a response to the rapid development in this nascent field, this article gives a comprehensive review on the structure features, theoretical methods for stability and property prediction, processing routes, novel properties, and prospective applications of HECs. The challenges on processing, characterization, and property predictions are also emphasized. Finally, future directions for new material exploration, novel processing, fundamental understanding, in-depth characterization, and database assessments are given.

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“…Since sound velocity is mainly determined by the compound itself through v s ∝( F / M ) 1/2 , in which F is the force constant and M is the atom mass in dense materials, it seems that there is no other way to reduce v s than to adjust the composition and thus the bond strength and atomic mass, which is typically accomplished in SnTe through Mn [ 12 ] and AgSbTe 2 [ 13 ] alloying or by introducing large mass/strain contrasts (massive disordered cations) to broaden the phonon dispersion. [ 14 ] Surprisingly, the Snyder group demonstrated that the lattice plane spacing of PbTe can be enlarged by introducing internal tensile strain, thus weakening the bonding stiffness, which was found to reduce the sound velocity and thus the lattice thermal conductivity. [ 15 ]…”

Section: Introductionmentioning

confidence: 99%

Ultrahigh Thermoelectric Performance in Environmentally Friendly SnTe Achieved through Stress‐Induced Lotus‐Seedpod‐Like Grain Boundaries

Guo

Cui

et al. 2021

Adv Funct Materials

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In an effort to improve the thermoelectric performance of the environmentally friendly SnTe, here, a multilevel structure composed of “lotus‐seedpod‐like” grain boundaries, dense dislocations, and nanopores is innovatively constructed, which synergistically reduces the sound velocity and the phonon relaxation time, resulting in ultralow lattice thermal conductivity throughout a wide temperature range. An ultrahigh figure of merit, ZT, of ≈1.7 and an unprecedented average ZT of ≈1 from 300 to 873 K are obtained. In contrast to the common pore‐forming method of volatilization, the strategy of stress‐induced recrystallization and gas expansion cogenerating interfacial pores that is used here, is believed to be more widely applicable for many other materials, which opens up a new avenue for improving thermoelectric performance.

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Atomic disordering advances thermoelectric group IV telluride alloys with a multiband transport

Cited by 28 publications

References 63 publications

Medium Entropy‐Enabled High Performance Cubic GeTe Thermoelectrics

Medium Entropy‐Enabled High Performance Cubic GeTe Thermoelectrics

High-entropy ceramics: Present status, challenges, and a look forward

Ultrahigh Thermoelectric Performance in Environmentally Friendly SnTe Achieved through Stress‐Induced Lotus‐Seedpod‐Like Grain Boundaries

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