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Keywords = heusler compound

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12 pages, 11870 KiB  
Article
Structural, Elastic, Electronic, Magnetic, and Half-Metallic Properties of Full-Heusler Compounds Fe2LiZ (Z = Ge and Si): A First-Principles Study
by Yufeng Wen, Yanlin Yu, Zhangli Lai and Xianshi Zeng
Metals 2025, 15(7), 808; https://doi.org/10.3390/met15070808 - 18 Jul 2025
Viewed by 225
Abstract
The structural, elastic, electronic, magnetic, and half-metallic properties of full-Heusler Fe2LiSi and Fe2LiGe compounds were investigated using first-principles calculations. Among the studied configurations, the cubic XA structures in the ferromagnetic state for both compounds are the most stable. They [...] Read more.
The structural, elastic, electronic, magnetic, and half-metallic properties of full-Heusler Fe2LiSi and Fe2LiGe compounds were investigated using first-principles calculations. Among the studied configurations, the cubic XA structures in the ferromagnetic state for both compounds are the most stable. They exhibit mechanical stability, elastic anisotropy, and ductility. Compared to Fe2LiGe, Fe2LiSi demonstrates higher stability, stronger anisotropy, greater brittleness, higher Debye and melting temperatures, and a smaller Grüneisen parameter. Both compounds exhibit metallic majority-spin channels and semiconducting minority-spin channels. At the equilibrium lattice constant, Fe2LiSi and Fe2LiGe exhibit half-metallic gaps of 0.141 eV and 0.179 eV, respectively. Both compounds exhibit 100% spin-polarization ratio in specific lattice constant ranges. The total magnetic moment per formula unit (3.000 μB) follows the generalized Slater–Pauling rule and depends on Fe atomic magnetic moments. These properties indicate that Fe2LiSi and Fe2LiGe hold promise for spintronic applications. Full article
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13 pages, 5053 KiB  
Article
Thermoelectric Properties of NbCoNixSn (x = 0–1)
by Moritz Thiem, Ruijuan Yan, Anke Weidenkaff and Wenjie Xie
Materials 2025, 18(13), 3189; https://doi.org/10.3390/ma18133189 - 5 Jul 2025
Viewed by 446
Abstract
The half-Heusler (HH) compound NbCoSn, with 18 valence electrons, is a promising thermoelectric (TE) material due to its favourable electrical properties and excellent thermal and chemical stability. Enhancing its TE performance typically involves doping and microstructure engineering. In this study, Ni was introduced [...] Read more.
The half-Heusler (HH) compound NbCoSn, with 18 valence electrons, is a promising thermoelectric (TE) material due to its favourable electrical properties and excellent thermal and chemical stability. Enhancing its TE performance typically involves doping and microstructure engineering. In this study, Ni was introduced into NbCoSn to form NbCoNixSn (x = 0–1), and the effects of Ni content on the microstructure and TE properties were systematically investigated. At low doping levels (x ≤ 0.05), Ni occupies interstitial sites, forming NbCoNixSn solid solutions. At higher concentrations (x > 0.05), full-Heusler (FH) secondary phases emerge, resulting in HH–FH composites. The introduction of Co/Ni interstitials enhances TE performance by creating in-gap electronic states and increasing phonon scattering through point defects. A clear structural transition from HH to FH phases is observed with increasing Ni content. The highest figure of merit, ZT ≈ 0.52 at 975 K, was obtained for NbCoNi0.05Sn, comparable to the best values reported for this system. Full article
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12 pages, 1250 KiB  
Article
Probing the Structural Order of Half-Heusler Phases in Sb-Doped (Ti,Zr,Hf)NiSn Thermoelectrics
by Fani Pinakidou, Andreas Delimitis and Maria Katsikini
Nanomaterials 2025, 15(13), 1037; https://doi.org/10.3390/nano15131037 - 3 Jul 2025
Viewed by 318
Abstract
The nanostructural features of a mechanically alloyed Sb-doped (Ti0.4Zr0.6)0.7Hf0.3NiSn thermoelectric (TE) Half-Heusler (HH) compound were addressed using Transmission Electron Microscopy (TEM) coupled with Energy Dispersive Spectroscopy measurements and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy. [...] Read more.
The nanostructural features of a mechanically alloyed Sb-doped (Ti0.4Zr0.6)0.7Hf0.3NiSn thermoelectric (TE) Half-Heusler (HH) compound were addressed using Transmission Electron Microscopy (TEM) coupled with Energy Dispersive Spectroscopy measurements and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy. The EXAFS measurements at the Ni-K, Sn-K, Zr-K, and Hf-L3-edge were implemented in an effort to reveal the influence of Hf and Zr incorporation into the crystal with respect to their previously measured TE properties. The substitution of Ti by Hf and Zr is expected to yield local lattice distortions due to the different atomic sizes of the dopants or/and electronic charge redistribution amongst the cations. However, the material is characterised by a high degree of crystallinity in both the short and long-range order, on average, and the nominal stoichiometry is identified as (Zr0.42Hf0.30Ti0.28)NiSn0.98Sb0.02. The synergistic effect of minimization of extended structural defects or lattice distortions and considerable alloying-induced point defect population contributes to the improved TE properties and leads to the previously reported enhancement of the figure of merit of the mixed HHs. Full article
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12 pages, 413 KiB  
Article
Towards Novel Spintronic Materials: Mg-Based d0-d Heusler (Nowotny–Juza) Compounds
by Kemal Özdoğan and Iosif Galanakis
Micromachines 2025, 16(6), 674; https://doi.org/10.3390/mi16060674 - 31 May 2025
Viewed by 766
Abstract
Heusler compounds and alloys constitute a burgeoning class of materials with exceptional properties, holding immense promise for advanced technologies. Electronic band structure calculations are instrumental in driving research in this field. Nowotny–Juza compounds are similar to Semi-Heusler compounds containing one instead of two [...] Read more.
Heusler compounds and alloys constitute a burgeoning class of materials with exceptional properties, holding immense promise for advanced technologies. Electronic band structure calculations are instrumental in driving research in this field. Nowotny–Juza compounds are similar to Semi-Heusler compounds containing one instead of two transition metal atoms in their chemical formula. Recently, they have been widely referred to as “p0-d or d0-d Semi-Heusler compounds”. Building upon our previous studies on p0-d or d0-d Semi-Heusler compounds featuring Li or K, we now explore a new class of d0-d compounds incorporating alkaline earth metals and more specifically Mg which is well-known to occupy all possible sites in Heusler compounds. These compounds, with the general formula MgZ(Ga, Ge, or As), where Z is a transition metal, are investigated for their structural, electronic, and magnetic properties, specifically within the context of the three possible C1b structures including also the effect of tetragonalization which is shown not to affect the equilibrium cubic type. Our findings demonstrate that a significant number of these compounds exhibit magnetic behavior, with several displaying half-metallicity, making them highly attractive for spintronic applications. This research provides a crucial foundation for future experimental investigations into these promising materials. Full article
(This article belongs to the Special Issue Magnetic Materials for Spintronics Devices)
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10 pages, 4065 KiB  
Article
Electronic Correlations in Ferromagnetic Heusler Alloy ln2MnW: Insights from First-Principles Calculations
by Abdul Munam Khan and Uzma Zahoor
Alloys 2025, 4(2), 5; https://doi.org/10.3390/alloys4020005 - 28 Mar 2025
Viewed by 805
Abstract
First-principles calculations were carried out to investigate the physical properties of the full-Heusler compound In2MnW. The WIEN2K code was utilized with various approximations, such as GGA and GGA+U, to analyze its structural, electronic, and magnetic properties. The unit cell was optimized [...] Read more.
First-principles calculations were carried out to investigate the physical properties of the full-Heusler compound In2MnW. The WIEN2K code was utilized with various approximations, such as GGA and GGA+U, to analyze its structural, electronic, and magnetic properties. The unit cell was optimized to determine the ground-state energy. The calculated formation enthalpy (ΔH) of In2MnW is −0.189 eV, indicating its thermodynamic stability due to the negative value. Band structure analysis using both potentials confirms the compound’s metallic nature, which is further supported by total density of states calculations. The total magnetic moment is found to be 4.3 µB, which slightly increases to 4.4 µB when the U parameter is included. These findings suggest that In2MnW demonstrates metallic ferromagnetic behavior, highlighting its potential as a promising ferromagnetic material for mass storage applications. Full article
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15 pages, 3182 KiB  
Article
Ab Initio Investigation of the Stability, Electronic, Mechanical, and Transport Properties of New Double Half Heusler Alloys Ti2Pt2ZSb (Z = Al, Ga, In)
by Nurgul S. Soltanbek, Nurpeiis A. Merali, Nursultan E. Sagatov, Fatima U. Abuova, Edgars Elsts, Aisulu U. Abuova, Vladimir V. Khovaylo, Talgat M. Inerbaev, Marina Konuhova and Anatoli I. Popov
Metals 2025, 15(3), 329; https://doi.org/10.3390/met15030329 - 18 Mar 2025
Cited by 2 | Viewed by 530
Abstract
This research aimed to explore the structural, electronic, mechanical, and vibrational properties of double half Heusler compounds with the generic formula Ti2Pt2ZSb (Z = Al, Ga, and In), using density functional theory calculations. The generalized gradient approximation within the [...] Read more.
This research aimed to explore the structural, electronic, mechanical, and vibrational properties of double half Heusler compounds with the generic formula Ti2Pt2ZSb (Z = Al, Ga, and In), using density functional theory calculations. The generalized gradient approximation within the PBE functional was employed for structural relaxation and for calculations of vibrational and mechanical properties and thermal conductivity, while the hybrid HSE06 functional was employed for calculations of the electronic properties. Our results demonstrate that these compounds are energetically favorable and dynamically and mechanically stable. Our electronic structure calculations revealed that the Ti2Pt2AlSb double half Heusler compound is a non-magnetic semiconductor with an indirect band gap of 1.49 eV, while Ti2Pt2GaSb and Ti2Pt2InSb are non-magnetic semiconductors with direct band gaps of 1.40 eV. Further analysis, including phonon dispersion curves, the electron localization function (ELF), and Bader charge analysis, provided insights into the bonding character and vibrational properties of these materials. These findings suggest that double half Heusler compounds are promising candidates for thermoelectric device applications and energy-conversion devices, due to their favorable properties. Full article
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12 pages, 3976 KiB  
Article
Magnetic and Thermoelectric Properties of Fe2CoGa Heusler Compounds
by Tetsuji Saito and Hayai Watanabe
Inorganics 2025, 13(2), 33; https://doi.org/10.3390/inorganics13020033 - 23 Jan 2025
Viewed by 842
Abstract
The investigation of the properties of Heusler compounds is an important task that will pave the way for new applications in various fields related to magnetics and thermoelectrics. This study examines the magnetic and thermoelectric properties of Fe2CoGa Heusler compounds prepared [...] Read more.
The investigation of the properties of Heusler compounds is an important task that will pave the way for new applications in various fields related to magnetics and thermoelectrics. This study examines the magnetic and thermoelectric properties of Fe2CoGa Heusler compounds prepared by casting and subsequent annealing. The Fe2CoGa Heusler compound was found to be ferromagnetic, with a large saturation magnetization of 110 emu/g and a high Curie temperature of 1011 K. The Fe2CoGa Heusler compound was a good thermoelectric material, with a negative Seebeck coefficient of −44 μV/K, a low electrical resistivity of 0.60 μΩm, and a high-power factor of 3000 μW/mK2 at room temperature. The maximum power factor of 3230 μW/mK2 for the Fe2CoGa Heusler compound was obtained at 400 K. In order to improve the magnetic and thermoelectric properties of the Fe2CoGa Heusler compound, Fe2-xCo1+xGa (x = 0–1) Heusler compounds were also prepared by casting and subsequent annealing. In the Fe2-xCo1+xGa (x = 0–1) Heusler compounds, the saturation magnetization slightly decreased, but the Curie temperature increased with increasing Co content (x). As regards the thermoelectric properties, the electrical resistivity of the Fe2-xCo1+xGa (x = 0.25–1) Heusler compounds was smaller than that of the Fe2CoGa Heusler compound. The Seebeck coefficient and power factor of the Fe1.75Co1.25Ga Heusler compound were more significant than those of the Fe2CoGa Heusler compound. An increase in the Co content of the Fe2CoGa Heusler compound did not improve the saturation magnetization but improved the Curie temperature and thermoelectric properties of the Fe2CoGa Heusler compound. The Fe1.75Co1.25Ga Heusler compound exhibited a high-power factor value of over 4000 μW/mK2, which was comparable to that of the Bi2Te3 compound. Full article
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11 pages, 3525 KiB  
Article
Effects of Ti and Sn Substitutions on Magnetic and Transport Properties of the TiFe2Sn Full Heusler Compound
by Bogdan Popescu, Ilhame Assahsahi, Magdalena Galatanu and Andrei Galatanu
Inorganics 2024, 12(12), 322; https://doi.org/10.3390/inorganics12120322 - 11 Dec 2024
Viewed by 815
Abstract
The synthesis of polycrystalline TiFe2Sn samples by a route including arc melting and spark plasma sintering with Hf, Y, and In substitutions at the Ti and Sn sites is investigated. For a reduced amount of substitution, around 2 at%, the samples [...] Read more.
The synthesis of polycrystalline TiFe2Sn samples by a route including arc melting and spark plasma sintering with Hf, Y, and In substitutions at the Ti and Sn sites is investigated. For a reduced amount of substitution, around 2 at%, the samples are single phase, while for increased amounts, secondary phases segregate. As is characteristic of these compounds, the Fe-Ti atomic disorder generates a weak ferromagnetic ordering, which is also influenced by the type of substitutional atoms and the secondary phases in the samples with a higher Hf content. The Seebeck coefficient values show an increase for Ti0.98Hf0.02Fe2Sn and for samples with an adjusted Sn content, resulting in slightly increased power factor values. These values reach a maximum for Ti0.98Hf0.02Fe2Sn at approximately 300 K and for TiFe2Sn1.05 at approximately 325 K, namely, 2.69 × 10⁻4 Wm−1K−2 and 2.52 × 10⁻4 Wm−1K−2, respectively. The thermal conductivity of all the samples with substitutions increases with respect to the pristine sample. The highest figure of merit value of 0.016 is also obtained for Ti0.98Hf0.02Fe2Sn at 325 K. Full article
(This article belongs to the Special Issue New Semiconductor Materials for Energy Conversion)
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12 pages, 612 KiB  
Article
Magnetic Properties of All-d Metallic Heusler Compounds: A First-Principles Study
by Murat Tas, Ersoy Şaşıoğlu and Iosif Galanakis
Magnetism 2024, 4(4), 400-411; https://doi.org/10.3390/magnetism4040026 - 10 Dec 2024
Viewed by 1861
Abstract
All-d metallic Heusler compounds are promising materials for nanoelectronic applications. Such materials combining 3d, 4d, and 5d atoms have not yet been studied. In this respect, we perform ab initio electronic structure calculations and focus on [...] Read more.
All-d metallic Heusler compounds are promising materials for nanoelectronic applications. Such materials combining 3d, 4d, and 5d atoms have not yet been studied. In this respect, we perform ab initio electronic structure calculations and focus on Co2MnZ, Rh2MnZ, and Ru2MnZ compounds, where Z represents transition metal atoms from groups 3B, 4B, 5B, and 6B of the periodic table. Our results demonstrate that most of these compounds exhibit a distinctive region of very low minority-spin state density at the Fermi level when crystallized in the L21 lattice structure. The Co-based compounds follow a Slater–Pauling behavior for their total spin magnetic moments, while the Ru-based compounds consistently deviate from the predicted Slater–Pauling values. Rh-based compounds show similarities to Co-based compounds for lighter Z atoms and to Ru-based compounds for heavier Z atoms. We find that the choice of the Z element within the same periodic table column has only a minor effect on the results, except for the Rh2Mn(Cr, Mo, W) compounds. Our findings suggest that these compounds hold significant promise for applications in spintronics and magnetoelectronics. Full article
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11 pages, 504 KiB  
Article
Interplay Between Structural, Electronic, and Magnetic Properties in the d0-d Semi-Heusler Compounds; the Case of the K-Based Compounds
by Kemal Özdoğan and Iosif Galanakis
Solids 2024, 5(4), 533-543; https://doi.org/10.3390/solids5040036 - 7 Nov 2024
Cited by 2 | Viewed by 1001
Abstract
Heusler compounds and alloys represent a rapidly expanding family of materials that exhibit novel properties of significant interest for advanced technological applications. Electronic band structure calculations play a pivotal role in advancing research in this area. In an earlier study, we explored the [...] Read more.
Heusler compounds and alloys represent a rapidly expanding family of materials that exhibit novel properties of significant interest for advanced technological applications. Electronic band structure calculations play a pivotal role in advancing research in this area. In an earlier study, we explored the properties of a new class of Heusler compounds based on Li, referred to as “p0-d semi-Heusler Compounds”. In this study, we take the research a step further by focusing on “d0-d semi-Heusler Compounds”, with the chemical formula KZ(Ga, Ge, As, or Se), where Z represents a transition metal. Our investigation centers on the structural, electronic, and magnetic properties of these compounds, particularly in relation to the three possible C1b structures. Most of these compounds are found to be magnetic and, notably, several among them exhibit half-metallicity making them appealing for applications in spintronics. Our findings provide a foundation for future experimental research on these materials. Full article
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12 pages, 600 KiB  
Article
Interplay between Structural, Electronic, and Magnetic Properties in the p0-d Semi-Heusler Compounds: The Case of Li-Based Compounds
by Kemal Özdoğan and Iosif Galanakis
Crystals 2024, 14(8), 693; https://doi.org/10.3390/cryst14080693 - 29 Jul 2024
Cited by 3 | Viewed by 1127
Abstract
Half-metallic semi-Heusler compounds (also known as half-Heusler compounds) are currently at the forefront of scientific research due to their potential applications in spintronic devices. Unlike other semi-Heuslers, the p0(d0)-d compounds do not appear to crystallize in [...] Read more.
Half-metallic semi-Heusler compounds (also known as half-Heusler compounds) are currently at the forefront of scientific research due to their potential applications in spintronic devices. Unlike other semi-Heuslers, the p0(d0)-d compounds do not appear to crystallize in the typical variant of the C1b structure. We investigate this phenomenon in the p0-d Heusler compounds LiYGa and LiYGe, where Y varies between Ca and Zn, using first-principles ab initio electronic band-structure calculations. We examine the electronic and magnetic properties of these compounds in relation to the three possible C1b structures. Notably, LiVGa, LiVGe, LiMnGa, and LiCrGe are half-metallic ferromagnets across all three variations of the C1b lattice structure. Our findings will serve as a foundation for future experimental studies on these compounds. Full article
(This article belongs to the Special Issue Magnetoelectric Materials and Their Application)
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18 pages, 6181 KiB  
Article
Growth of Carbon Nanofibers and Carbon Nanotubes by Chemical Vapour Deposition on Half-Heusler Alloys: A Computationally Driven Experimental Investigation
by Ioannis G. Aviziotis, Apostolia Manasi, Afroditi Ntziouni, Georgios P. Gakis, Aikaterini-Flora A. Trompeta, Xiaoying Li, Hanshan Dong and Costas A. Charitidis
Materials 2024, 17(13), 3144; https://doi.org/10.3390/ma17133144 - 27 Jun 2024
Viewed by 1171
Abstract
The possibility of directly growing carbon nanofibers (CNFs) and carbon nanotubes (CNTs) on half-Heusler alloys by Chemical Vapour Deposition (CVD) is investigated for the first time, without using additional catalysts, since the half-Heusler alloys per se may function as catalytic substrates, according to [...] Read more.
The possibility of directly growing carbon nanofibers (CNFs) and carbon nanotubes (CNTs) on half-Heusler alloys by Chemical Vapour Deposition (CVD) is investigated for the first time, without using additional catalysts, since the half-Heusler alloys per se may function as catalytic substrates, according to the findings of the current study. As a carbon source, acetylene is used in the temperature range of 700–750 °C. The n-type half-Heusler compound Zr0.4Ti0.60.33Ni0.33Sn0.98Sb0.020.33 is utilized as the catalytic substrate. At first, a computational model is developed for the CVD reactor, aiming to optimize the experimental process design and setup. The experimental process conditions are simulated to investigate the reactive species concentrations within the reactor chamber and the activation of certain reactions. SEM analysis confirms the growth of CNFs with diameters ranging from 450 nm to 1 μm. Raman spectroscopy implies that the formed carbon structures resemble CNFs rather than CNTs, and that amorphous carbon also co-exists in the deposited samples. From the characterization results, it may be concluded that a short reaction time and a low acetylene flow rate lead to the formation of a uniform CNF coating on the surface of half-Heusler alloys. The purpose of depositing carbon nanostructures onto half-Heusler alloys is to improve the current transfer, generated from these thermoelectric compounds, by forming a conductive coating on their surface. Full article
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25 pages, 4342 KiB  
Review
Crystal Structure and Properties of Heusler Alloys: A Comprehensive Review
by Asma Wederni, Jason Daza, Wael Ben Mbarek, Joan Saurina, Lluisa Escoda and Joan-Josep Suñol
Metals 2024, 14(6), 688; https://doi.org/10.3390/met14060688 - 10 Jun 2024
Cited by 19 | Viewed by 7800
Abstract
Heusler alloys, which were unintentionally discovered at the start of the 20th century, have become intriguing materials for many extraordinary functional applications in the 21st century, including smart devices, spintronics, magnetic refrigeration and the shape memory effect. With this review article, we would [...] Read more.
Heusler alloys, which were unintentionally discovered at the start of the 20th century, have become intriguing materials for many extraordinary functional applications in the 21st century, including smart devices, spintronics, magnetic refrigeration and the shape memory effect. With this review article, we would like to provide a comprehensive review on the recent progress in the development of Heusler alloys, especially Ni-Mn based ones, focusing on their structural crystallinity, order-disorder atoms, phase changes and magnetic ordering atoms. The characterization of the different structures of these types of materials is needed, where a detailed exploration of the crystal structure is presented, encompassing the influence of temperature and compositional variations on the exhibited phases. Hence, this class of materials, present at high temperatures, consist of an ordered austenite with a face-centered cubic (FCC) superlattice as an L21 structure, or body-centered cubic (BCC) unit cell as a B2 structure. However, a low-temperature martensite structure can be produced as an L10, 10M or 14M martensite structures. The crystal lattice structure is highly dependent on the specific elements comprising the alloy. Additionally, special emphasis is placed on phase transitions within Heusler alloys, including martensitic transformations ranging above, near or below room temperature and magnetic transitions. Therefore, divers’ crystallographic defects can be presented in such types of materials affecting their structural and magnetic properties. Moreover, an important property of Heusler compounds, which is the ability to regulate the valence electron concentration through element substitution, is discussed. The possible challenges and remaining issues are briefly discussed. Full article
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16 pages, 6204 KiB  
Article
Crucial Role of Ni Point Defects and Sb Doping for Tailoring the Thermoelectric Properties of ZrNiSn Half-Heusler Alloy: An Ab Initio Study
by Eleonora Ascrizzi, Chiara Ribaldone and Silvia Casassa
Materials 2024, 17(5), 1061; https://doi.org/10.3390/ma17051061 - 25 Feb 2024
Cited by 1 | Viewed by 1590
Abstract
In the wide group of thermoelectric compounds, the half-Heusler ZrNiSn alloy is one of the most promising materials thanks to its thermal stability and narrow band gap, which open it to the possibility of mid-temperature applications. A large variety of defects and doping [...] Read more.
In the wide group of thermoelectric compounds, the half-Heusler ZrNiSn alloy is one of the most promising materials thanks to its thermal stability and narrow band gap, which open it to the possibility of mid-temperature applications. A large variety of defects and doping can be introduced in the ZrNiSn crystalline structure, thus allowing researchers to tune the electronic band structure and enhance the thermoelectric performance. Within this picture, theoretical studies of the electronic properties of perfect and defective ZrNiSn structures can help with the comprehension of the relation between the topology of defects and the thermoelectric features. In this work, a half-Heusler ZrNiSn alloy is studied using different defective models by means of an accurate Density Functional Theory supercell approach. In particular, we decided to model the most common defects related to Ni, which are certainly present in the experimental samples, i.e., interstitial and antisite Ni and a substitutional defect consisting of the replacement of Sn with Sb atoms using concentrations of 3% and 6%. First of all, a comprehensive characterization of the one-electron properties is performed in order to gain deeper insight into the relationship between structural, topological and electronic properties. Then, the effects of the modeled defects on the band structure are analyzed, with particular attention paid to the region between the valence and the conduction bands, where the defective models introduce in-gap states with respect to the perfect ZrNiSn crystal. Finally, the electronic transport properties of perfect and defective structures are computed using semi-classical approximation in the framework of the Boltzmann transport theory as implemented in the Crystal code. The dependence obtained of the Seebeck coefficient and the power factor on the temperature and the carrier concentration shows reasonable agreement with respect to the experimental counterpart, allowing possible rationalization of the effect of the modeled defects on the thermoelectric performance of the synthesized samples. As a general conclusion, defect-free ZrNiSn crystal appears to be the best candidate for thermoelectric applications when compared to interstitial and antisite Ni defective models, and substitutional defects of Sn with Sb atoms (using concentrations of 3% and 6%) do not appreciably improve electronic transport properties. Full article
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11 pages, 455 KiB  
Article
Machine Learning-Based Predictions for Half-Heusler Phases
by Kaja Bilińska and Maciej J. Winiarski
Inorganics 2024, 12(1), 5; https://doi.org/10.3390/inorganics12010005 - 22 Dec 2023
Cited by 5 | Viewed by 2553
Abstract
Machine learning models (Support Vector Regression) were applied for predictions of several targets for 18-electron half-Heusler phases: a lattice parameter, a bulk modulus, a band gap, and a lattice thermal conductivity. The training subset, which consisted of 47 stable phases, was studied with [...] Read more.
Machine learning models (Support Vector Regression) were applied for predictions of several targets for 18-electron half-Heusler phases: a lattice parameter, a bulk modulus, a band gap, and a lattice thermal conductivity. The training subset, which consisted of 47 stable phases, was studied with the use of Density Functional Theory calculations with two Exchange-Correlation Functionals employed (GGA, MBJGGA). The predictors for machine learning models were defined among the basic properties of the elements. The most optimal combinations of predictors for each target were proposed and discussed. Root Mean Squared Errors obtained for the best combinations of predictors for the particular targets are as follows: 0.1 Å (lattice parameters), 11–12 GPa (bulk modulus), 0.22 eV (band gaps, GGA and MBJGGA), and 9–9.5 W/mK (lattice thermal conductivity). The final results of the predictions for a large set of 74 semiconducting half-Heusler compounds were disclosed and compared to the available literature and experimental data. The findings presented in this work encourage further studies with the use of combined machine learning and ab initio calculations. Full article
(This article belongs to the Special Issue Advances of Thermoelectric Materials)
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