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Accurate determination of the intrinsic electronic structure of thermoelectric materials is a prerequisite for utilizing an electronic band engineering strategy to improve their thermoelectric performance. Herein, with high‐resolution angle‐resolved photoemission spectroscopy (ARPES), the intrinsic electronic structure of the 3D half‐Heusler thermoelectric material ZrNiSn is revealed. An unexpectedly large intrinsic bandgap is directly observed by ARPES and is further confirmed by electrical and optical measurements and first‐principles calculations. Moreover, a large anisotropic conduction band with an anisotropic factor of 6 is identified by ARPES and attributed to be one of the most important reasons leading to the high thermoelectric performance of ZrNiSn. These successful findings rely on the grown high‐quality single crystals, which have fewer Ni interstitial defects and negligible in‐gap states on the electronic structure. This work demonstrates a realistic paradigm to investigate the electronic structure of 3D solid materials by using ARPES and provides new insights into the intrinsic electronic structure of the half‐Heusler system benefiting further optimization of thermoelectric performance. Herein, the intrinsic electronic structure of archetypical 3D ZrNiSn half‐Heusler compound is resolved using angle‐resolved photoemission spectroscopy. Unexpectedly large intrinsic bandgap and anisotropic conduction characteristics are directly revealed. These results provide new insights into the origin of high power factor of half‐Heuslers and offer a new strategy to further optimize their thermoelectric properties.

Conversion efficiency and output power are crucial parameters for thermoelectric power generation that highly rely on figure of merit ZT and power factor (PF), respectively. Therefore, the synergistic optimization of electrical and thermal properties is imperative instead of optimizing just ZT by thermal conductivity reduction or just PF by electron transport enhancement. Here, it is demonstrated that Nb0.95Hf0.05FeSb has not only ultrahigh PF over ≈100 µW cm−1 K−2 at room temperature but also the highest ZT in a material system Nb0.95M0.05FeSb (M = Hf, Zr, Ti). It is found that Hf dopant is capable to simultaneously supply carriers for mobility optimization and introduce atomic disorder for reducing lattice thermal conductivity. As a result, Nb0.95Hf0.05FeSb distinguishes itself from other outstanding NbFeSb‐based materials in both the PF and ZT. Additionally, a large output power density of ≈21.6 W cm−2 is achieved based on a single‐leg device under a temperature difference of ≈560 K, showing the realistic prospect of the ultrahigh PF for power generation. A material system Nb0.95M0.05FeSb (M = Hf, Zr, Ti) with an ultrahigh power factor (PF) around 100 µW cm−1 K−2 at room temperature is demonstrated. It shows a superior PF compared to other high‐performance thermoelectric materials within a wide temperature range. In this system, Nb0.95Hf0.05FeSb is noticeable for suppressing lattice thermal conductivity while the ultrahigh PF is maintained, contributing to a significantly improved figure of merit, ZT.

Structural, electronic, elastic, and transport properties of FeVX (X = As, P) half-Heusler (HH) compounds have been calculated using density functional theory (DFT). The generalized gradient approximation developed by Perdew–Burke–Ernzerhof (GGA-PBE) is utilized for the calculation of the structural properties and the mechanical parameters of FeVX (X = As, P), indicating that the studied compounds are mechanically stable. The Tran and Blaha-modified Becke–Johnson potential (TB-mBJ) is utilized to improve the investigation of the electronic structure and also indicates that the FeVX (X = As, P) compounds are narrow-gap semiconductors. Calculations of transport efficiency are performed using the semiclassical Boltzmann theory. The figure of merit ZT is near unity at room temperature, indicating that both compounds are good candidates for use in transport devices.

This study presents a comprehensive first-principles investigation of the structural, mechanical, electronic, optical, thermoelectric, and thermodynamic properties of half-Heusler PtTiZ (Z = Ge, Pb) compounds using the full-potential linearized augmented plane-wave (FP-LAPW) method combined with semiclassical Boltzmann transport theory. Exchange–correlation effects were treated within the LDA, PBE-GGA, and Tran–Blaha modified Becke–Johnson (TB-mBJ) schemes to achieve accurate electronic descriptions. Both alloys crystallize in a stable cubic F-43 m structure and exhibit indirect semiconducting behavior with band gaps of 0.66 eV (PtTiGe) and 0.387 eV (PtTiPb). The density-of-states analysis indicates that the valence region is dominated by Ti-3 d and Z- p hybridized states, confirming strong p–d interactions. Mechanical stability criteria and positive elastic constants verify that both compounds are mechanically robust, with PtTiGe being stiffer and harder than PtTiPb. Optical results reveal pronounced absorption and high optical conductivity in the ultraviolet region, suggesting potential for optoelectronic applications. Thermoelectric analysis demonstrates p -type character with Seebeck coefficients of 229.21 µV K⁻¹ (PtTiGe) and 236.21 µV K⁻¹ (PtTiPb) at 300 K, and 235.05 µV K⁻¹ and 237.31 µV K⁻¹ at 1200 K, respectively. The corresponding lattice thermal conductivities decrease to 0.45 W m⁻¹ K⁻¹ and 0.32 W m⁻¹ K⁻¹, yielding maximum dimensionless figures of merit ( ZT ) of 0.68 and 0.70 at 1200 K. Thermodynamic results confirm that the Debye temperature increases with pressure while heat capacity decreases, ensuring stability at elevated conditions. Overall, the synergistic combination of electronic tunability, optical responsiveness, and favorable thermoelectric performance highlights PtTiZ (Z = Ge, Pb) as promising candidates for high-temperature thermoelectric and ultraviolet-optoelectronic applications.

Half-Heusler phases (space group F 4 ¯ 3 m , C1b) have recently captured much attention as promising thermoelectric materials for heat-to-electric power conversion in the mid-to-high temperature range. The most studied ones are the RNiSn-type half-Heusler compounds, where R represents refractory metals Hf, Zr, and Ti. These compounds have shown a high-power factor and high-power density, as well as good material stability and scalability. Due to their high thermal conductivity, however, the dimensionless figure of merit (zT) of these materials has stagnated near 1 for a long time. Since 2013, the verifiable zT of half-Heusler compounds has risen from 1 to near 1.5 for both n- and p-type compounds in the temperature range of 500–900 °C. In this brief review, we summarize recent advances as well as approaches in achieving the high zT reported. In particular, we discuss the less-exploited strain-relief effect and dopant resonant state effect studied by the author and his collaborators in more detail. Finally, we point out directions for further development.

N-type half-Heusler NbCoSn is a promising thermoelectric material due to favourable electronic properties. It has attracted much attention for thermoelectric applications while the desired p-type NbCoSn counterpart shows poor thermoelectric performance. In this work, p-type NbCoSn has been obtained using Sc substitution at the Nb site, and their thermoelectric properties were investigated. Of all samples, Nb 0.95 Sc 0.05 CoSn compound shows a maximum power factor of 0.54 mW/mK 2 which is the highest among the previously reported values of p-type NbCoSn. With the suppression of thermal conductivity, p-type Nb 0.95 Sc 0.05 CoSn compound shows the highest measured figure of merit ZT = 0.13 at 879 K.

Magnetism plays a crucial role in advanced technologies and fundamental materials science. Among various magnetic materials, compounds incorporating rare earth elements with non-collinear magnetic orders have garnered significant attention. In this study, we investigate different magnetic orders in Pr(Ni, Pt)Bi compounds using density functional theory (DFT), incorporating the Hubbard on-site interaction for the Pr atom. The results indicate that the antiferromagnetic (AFM) order is the most stable phase in these compounds, with an energy several meV lower than the considered non-collinear orders. Furthermore, band inversion, a characteristic feature of topological properties, is observed in both cases. We also assess the distance-dependent exchange interactions within these structures. The findings have significant implications for the development of advanced spintronic devices, magnetic sensors, and novel magnetic materials with topological properties, paving the way for innovative applications in modern technology.

Research shows that the thermoelectric properties of topologically nontrivial semimetallic half-Heulser compounds can be optimized by topological phase transitions. Using density functional theory, we have found that the topologically semimetallic HfIrBi compound can be converted into semiconductors under hydrostatic pressures. We further investigate the band structures, phonon dispersions, and thermoelectric properties of the p-type HfIrBi compound under different hydrostatic pressures. The maximum ZT value of the p-type HfIrBi compound under 25 GPa pressure at 1000 K can reach 1.43, which is approximately 2.46 times larger than that without hydrostatic pressure. Therefore, the topological phase transitions induced by hydrostatic pressures point to the synthesis of new thermoelectric materials.

In this study, we have predicted the ground-state properties of the half-Heusler RuCrSb compound using the plane-wave pseudopotential method. The structural optimization signifies that the material is energetically favoured in the ferrimagnetic state in α-phase with optimized lattice parameter 6.025 Å. The positive cohesive energy as well as elastic constants indicate that the compound is thermodynamically and mechanically stable. The absence of a negative phonon dispersion curve also confirms that the sample material is dynamically durable. In order to explore the nature of bonding forces and determine the mechanical strength of the system, the elastic properties have been computed. Moreover, using the quasi-harmonic Debye model, it has been possible to determine the thermodynamical properties with regard to temperature for various pressures. For the strongly correlated d- transition electrons of the studied compound, we incorporated on-site Coulomb repulsion term ( U ) on GGA scheme during electronic and magnetic calculations. The studied compound reveals half-metallic performance, i.e., it conveys 100% spin polarization at the Fermi energy level ( E F ) under both GGA and GGA + U approximations. The total magnetic moments ( M t ) of the sample material is 1 μ B , which is in good agreement with the 18 Slater-Pauling rule; i.e., M t = Z t – 18. The magnetism source is predominantly from the Cr atom in the studied compound. Moreover, the electronic properties are also supported by the fermi surface, charge density distribution and the Bader charge method. As the Curie temperature ( T C ) of the studied material is observed to be higher than room temperature; the material is suitable for spintronic applications.

We have studied the half-Heusler compounds RhVZ (Z = P, As, Sb) using Density Functional Theory (DFT). The method of the Full Potential Linearly Augmented Plane Wave (FP-LAPW) is employed in the Wien2k package for calculation of structural, elastic, mechanical, electronic, magnetic, and optical properties. Lattice constants are found in the range 5.67 − 5.80 Å. Analysis of elastic properties shows that two of the compounds namely RhVP and RhVAs are ductile while RhVSb is brittle in nature. All three compounds are half-metals as revealed from the band structures and Density of States (DoS) calculations. In all of them, spin-down channels have the small band gaps, while spin-up channels are conducting. These compounds follow the Slater-Pauling 18 (MTot = ZTot − 18) electron rule with the total magnetic moments in the range 1 − 2 μB. Optical properties like dielectric function, refractive index, reflectivity, conductivity, and absorption coefficient are calculated and discussed.