Strategies and challenges of high-pressure methods applied to thermoelectric materials

Morozova, N. V.; Korobeinikov, Igor V.; Ovsyannikov, Sergey V.

doi:10.1063/1.5094166

Cited by 46 publications

(27 citation statements)

References 205 publications

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“…The positive S for all samples confirms that holes are the dominant mobile charge carriers in these films, as expected 23,24,25 . The Seebeck coefficient monotonously increases with strain (from compressive to tensile) in agreement with the decrease of the electrical conductivity 24,50 , by almost a factor two from 127 V K -1 (compressive) to 208 V K -1 (tensile), consistently with other observations made on various thermoelectric materials under highpressures (S decreasing with pressure) 49 . It is worth noting that the Seebeck coefficients of the almost relaxed LSCO film on LSAT (160 V K -1 ) and another moderately tensile on STO substrate (180 V K -1 , see Supporting Information, Fig.…”

Section: Resultssupporting

confidence: 89%

Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO₃ Transparent Thin Films

Han

Moalla

Fina

et al. 2021

ACS Appl. Electron. Mater.

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The impact of epitaxial strain on the structural, electronic, and thermoelectric properties of p-type transparent Sr-doped LaCrO3 thin films has been investigated. For this purpose, high-quality fully-strained La0.75Sr0.25CrO3 (LSCO) epitaxial thin films were grown by molecular beam epitaxy on three different (pseudo)cubic ( 001)-oriented perovskite-oxide substrates: LaAlO3, (LaAlO3)0.3(Sr2AlTaO6)0.7, and DyScO3. The lattice mismatch between the LSCO films and the substrates induces in-plane strain ranging from -2.06% (compressive) to +1.75% (tensile). The electric conductivity can be controlled over two orders of magnitude, σ ranging from ~0.5 S cm -1 (tensile strain) to 35 S cm -1 (compressive strain). Consistently, the Seebeck coefficient S can be finely tuned by a factor of almost two from ~127 µV K -1 (compressive strain) to 208 µV K -1 (tensile strain). Interestingly, we show that the thermoelectric power factor (PF = S 2 σ) can consequently be tuned by almost two orders of magnitude. The compressive strain yields a remarkable enhancement by a factor of three for 2% compressive strain with respect to almost relaxed films. These results demonstrate that epitaxial strain is a powerful lever to control the electric properties of LSCO and enhance its thermoelectric properties, which is of high interest for various devices and key applications such as thermal energy harvesters, coolers, transparent conductors, photo-catalyzers and spintronic memories.

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Section: Resultssupporting

confidence: 89%

Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO₃ Transparent Thin Films

Han

Moalla

Fina

et al. 2021

ACS Appl. Electron. Mater.

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“…Moreover, recent studies in thermoelectric materials show that Seebeck coefficients can increase with increasing pressures and temperatures (Chen et al. 2019; Morozova, Korobeinikov & Ovsyannikov 2019; Yoshino et al. 2020).…”

Section: Discussionmentioning

confidence: 99%

Thermoelectric precession in turbulent magnetoconvection

Horn

Aurnou

2021

J. Fluid Mech.

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We present laboratory measurements of the interaction between thermoelectric currents and turbulent magnetoconvection. In a cylindrical volume of liquid gallium heated from below and cooled from above and subject to a vertical magnetic field, it is found that the large-scale circulation (LSC) can undergo a slow axial precession. Our experiments demonstrate that this LSC precession occurs only when electrically conducting boundary conditions are employed, and that the precession direction reverses when the axial magnetic field direction is flipped. A thermoelectric magnetoconvection (TEMC) model is developed that successfully predicts the zeroth-order magnetoprecession dynamics. Our TEMC magnetoprecession model hinges on thermoelectric current loops at the top and bottom boundaries, which create Lorentz forces that generate horizontal torques on the overturning large-scale circulatory flow. The thermoelectric torques in our model act to drive a precessional motion of the LSC. This model yields precession frequency predictions that are in good agreement with the experimental observations. We postulate that thermoelectric effects in convective flows, long argued to be relevant in liquid metal heat transfer and mixing processes, may also have applications in planetary interior magnetohydrodynamics.

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m ) structure.…”

Section: Introductionmentioning

confidence: 99%

“…[12] These materials are narrow bandgap semiconductors and typical thermoelectrics and the effect of high pressures could increase their Seebeck coefficient. [13] However, phases formed at high pressures and room temperature, are unstable at normal conditions: their recovered high-pressure crystalline structure returns to the initial, rhombohedral (R 3m) structure.Very little is known about metastable phases of sesquichalcogenides of elements of the bismuth subgroup, obtained after high-pressure-high-temperature (HPHT) treatment and retained under ambient conditions. Earlier Vereschagin et al [14] found an irreversible polymorphic transition at 6.5-12 GPa and 1075 K in Bi 2 Se 3 .…”

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confidence: 99%

New Metastable Phase of Bismuth (III) Selenide: Crystal Structure and Electrical Properties

Serebryanaya

Буга

Баграмов

et al. 2020

Physica Status Solidi (b)

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Using high‐pressure–high‐temperature treatment at P = 4–7.7 GPa; T = 1373–1473 K with subsequent quenching, a new metastable phase of bismuth selenide (m‐Bi2Se3) is synthesized and its crystal structure, electrical resistivity, and annealing at heating are investigated. Using X‐ray powder diffraction, and analogy with high‐pressure structures of the rare‐earth element sesquichalcogenides, the crystal structure of the new metastable phase of m‐Bi2Se3 is determined as an orthorhombic distorted cation‐deficient structure of the Th3P4 type with the Fdd2 space group and Z = 10.66. The unit‐cell dimensions are: a = 13.4660(7) Å, b = 12.7772(7) Å, c = 9.0896(5) Å. The density of m‐Bi2Se3 (7.47 g cm−3) is slightly less than the initial rhombohedral phase of Bi2Se3, but the coordination number (CN) = 8 is higher than CN = 6 of the initial phase. The period of stability under ambient conditions of the new m‐Bi2Se3 phase is only about 2 months. After 300 °C annealing, m‐Bi2Se3 completely returns to the initial layered structure, and differential scanning calorimetry confirms that the reverse transformation as well as the direct transition occur through an amorphous state. The new phase is a narrow bandgap semiconductor with the energy gap of about 80 meV.

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Strategies and challenges of high-pressure methods applied to thermoelectric materials

Cited by 46 publications

References 205 publications

Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO₃ Transparent Thin Films

Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO₃ Transparent Thin Films

Thermoelectric precession in turbulent magnetoconvection

New Metastable Phase of Bismuth (III) Selenide: Crystal Structure and Electrical Properties

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Strategies and challenges of high-pressure methods applied to thermoelectric materials

Cited by 46 publications

References 205 publications

Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO3 Transparent Thin Films

Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO3 Transparent Thin Films

Thermoelectric precession in turbulent magnetoconvection

New Metastable Phase of Bismuth (III) Selenide: Crystal Structure and Electrical Properties

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Product

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Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO₃ Transparent Thin Films

Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO₃ Transparent Thin Films