Thermoelectric Properties of the As/P-Based Zintl Compounds EuIn2As2−xPx (X = 0 to 2) and SrSn2As2

Shinozaki, Kazuo; Goto, Yosuke; Hoshi, Kazuhisa; Kiyama, Ryosuke; Nakamura, Naoto; Miura, Akira; Moriyoshi, Chikako; Kuroiwa, Yoshihiro; Usui, Hidetomo; Mizuguchi, Yoshikazu

doi:10.26434/chemrxiv.14417759.v1

Cited by 3 publications

(6 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The experimentally saturated magnetic moment for Eu ions is ∼ 7.0 µ B that is close to the magnetic moment of f 7 state and our calculated value of 6.90 µ B . This indicates that Eu oxidation state is +2 similar to the oxidation state of Sr. A tunable Sr 1−x Eu x In 2 (As, P) 2 system thus can be achievable for realizing distinct topological magnetic states [42,43]. The dependence of the bandgap on the lattice constant (Fig.…”

Section: (I)] It Has An Anisotropic Energy Dispersion Indicating That...mentioning

confidence: 99%

“…Using this approach as a guiding principle, we identify here the SrIn 2 As 2 class of Zintl materials with the general formula AM 2 X 2 (A = alkali, alkaline earth, or rare-earth, M = post-transition metal; and X = Group IV or V element) in P 6 3 /mmc space group as a materials family that can support magnetic and nonmagnetic topological phases with substantial flexibility of manipulation through external controls. The Zintl has attracted great interest since its discovery owing to its fascinating electronic, topological, and magnetic properties [33][34][35][36][37][38][39][40][41][42][43].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Magnetically tunable Dirac and Weyl fermions in the Zintl materials family

Sarkar,

Mardanya,

Huang

et al. 2022

Preprint

View full text Add to dashboard Cite

Recent classification efforts encompassing crystalline symmetries have revealed rich possibilities for solid-state systems to support a tapestry of exotic topological states. However, finding materials that realize such states remains a daunting challenge. Here we show how the interplay of topology, symmetry, and magnetism combined with doping and external electric and magnetic field controls can be used to drive the previously unreported SrIn2As2 materials family into a variety of topological phases. Our first-principles calculations and symmetry analysis reveal that SrIn2As2 is a dual topological insulator with Z2 = (1; 000) and mirror Chern number CM = −1. Its isostructural and isovalent antiferromagnetic cousin EuIn2As2 is found to be an axion insulator with Z4 = 2. The broken time-reversal symmetry via Eu doping in Sr1−xEuxIn2As2 results in a higher-order or topological crystalline insulator state depending on the orientation of the magnetic easy axis. We also find that antiferromagnetic EuIn2P2 is a trivial insulator with Z4 = 0, and that it undergoes a magnetic field-driven transition to an ideal Weyl fermion or nodal fermion state with Z4 = 1 with applied magnetic field. Our study identifies Sr1−xEuxIn2(As, P)2 as a new tunable materials platform for investigating the physics and applications of Weyl and nodal fermions in the scaffolding of crystalline and axion insulator states.

show abstract

Section: (I)] It Has An Anisotropic Energy Dispersion Indicating That...mentioning

confidence: 99%

mentioning

confidence: 99%

Magnetically tunable Dirac and Weyl fermions in the Zintl materials family

Sarkar,

Mardanya,

Huang

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Polycrystalline EuCuAs was prepared by reacting EuAs and Cu (99.9%) in a similar manner to the method employed in our previous studies. 27,28,39 EuAs was prepared by reacting, in a 1:1 stoichiometric ratio, Eu (99.9%) with As (99.9999%) at 1123 K for 10 h in a carbonized silica tube. We scraped the surface of the Eu ingot mechanically by filing the surface prior to use.…”

Section: Sample Preparationmentioning

confidence: 99%

“…However, recent first-principles calculations show that cross-plane orbital overlap is important to induce axis-dependent conduction polarity. 27 This cross-plane orbital overlap tends to reduce the structural anisotropy in the materials. Therefore, to obtain the sufficient preferred orientation and/or texturing in these compounds can be regarded as a cutting edge to develop the materials with axis-dependent conduction polarity.…”

Section: Thermoelectric Transport Of Eu1-xnaxcuasmentioning

confidence: 99%

“…22,23 However, recent studies have demonstrated that As-based Zintl compounds can also show promising thermoelectric properties. [24][25][26][27][28] For example, BaCd2As2-based materials exhibit ZT = 0.81 at 762 K upon optimization of carrier concentration. 25 The crystal structure of EuCuAs (hexagonal P63/mmc space group), which is one of ABX-type Zintl compounds, consists of a honeycomb-type [CuAs] network sandwiched by Eu 2+ ions, 29 as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermoelectric properties of Zintl arsenide EuCuAs

Nakamura

Goto

Nakahira

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

We demonstrate thermoelectric transport properties of Zintl arsenide EuCuAs. The crystal structure of EuCuAs (hexagonal P63/mmc space group) consists of a covalently-bonded honeycomb-type [CuAs] network sandwiched by Eu2+ ions. Undoped EuCuAs exhibit the thermoelectric power factor of 1.2 and 0.4 mW/mK2 at 673 K along directions perpendicular and parallel to the uniaxial hot-pressing direction, respectively. Despite the relatively high power factor, dimensionless figure of merit is limited to 0.1 at 673 K due to the high lattice thermal conductivity, >2.0 W/mK. In addition to relatively high power factor, first-principles calculations predicted that, owing to a peculiar shape of the Fermi surface, heavy hole doped EuCuAs with hole concentration of >1.5 x 10^21 cm^-3 will exhibit the axis-dependent conduction polarity, which enables us to construct the transverse thermoelectric devices. We investigated the synthesis and thermoelectric transport properties of Eu1-xNaxCuAs using sodium (Na) as a hole dopant, resulting in a hole concentration of 1.0 x 10^21 cm^-3. The absolute value of the Seebeck coefficient decreased by Na-doping, as predicted by first-principles calculations, but no conduction polarity switching was observed. This may have resulted from insufficient hole concentration and/or preferred orientation of the samples.

show abstract

Physics and technology of thermoelectric materials and devices

Dadhich

Saminathan

Kumari

et al. 2023

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

The continuous depletion of fossil fuels and the increasing demand for eco-friendly and sustainable energy sources have prompted researchers to look for alternative energy sources. The loss of thermal energy in heat engines (100-350 ºC), coal-based thermal plants (150-700 ºC), heated water pumping in the geothermal process (150-700 ºC), and burning of petrol in the automobiles (150-250 ºC) in form of untapped waste-heat can be directly and/or reversibly converted into usable electricity by means of charge carriers (electrons or holes) as moving fluids using thermoelectric (TE) technology, which works based on typical Seebeck effect. The enhancement in TE conversion efficiency has been a key challenge because of the coupled relation between thermal and electrical transport of charge carriers in a given material. In this review, we have deliberated the physical concepts governing the materials to device performance as well as key challenges for enhancing the TE performance. Moreover, the role of crystal structure in the form of chemical bonding, crystal symmetry, order-disorder and phase transition on charge carrier transport in the material has been explored. Further, this review has also emphasized some insights on various approaches employed recently to improve the TE performance, such as, (i). carrier engineering via band engineering, low dimensional effects, and energy filtering effects and (ii). Phonon engineering via doping/alloying, nano-structuring, embedding secondary phases in the matrix and microstructural engineering. Wehave also briefed the importance of magnetic elements on thermoelectric properties of the selected materials and spin Seebeck effect. Furthermore, the design and fabrication of TE modules and their major challenges are also discussed. As, thermoelectric figure of merit, zT does not have any theoretical limitation, an ideal high performance thermoelectric device should consist of low-cost, eco-friendly, efficient, n- or p-type materials that operate at wide- temperature range and similar coefficients of thermal expansion, suitable contact materials, less electrical/ thermal losses and constant source of thermal energy. Overall, this review provides the recent physical concepts adopted and fabrication procedures of TE materials and device so as to improve the fundamental understanding and to develop a promising TE device.

show abstract

Thermoelectric Properties of the As/P-Based Zintl Compounds EuIn2As2−xPx (X = 0 to 2) and SrSn2As2

Cited by 3 publications

References 34 publications

Magnetically tunable Dirac and Weyl fermions in the Zintl materials family

Magnetically tunable Dirac and Weyl fermions in the Zintl materials family

Thermoelectric properties of Zintl arsenide EuCuAs

Physics and technology of thermoelectric materials and devices

Contact Info

Product

Resources

About