Credit: Zhuoyang TiExploration of Off-Stoichiometry Heusler CompoundsSome off-stoichiometry Heusler substances have actually been anticipated to display semiconductor attributes. The bonding habits in these S-P semiconductors and the relationship between their crystal structure and thermoelectric efficiency have stayed unclear.In-Depth Research on Heusler SystemsIn this research, the group focused on two Heusler systems: Ti-Fe-Sb and M-Co-Sn (M = Ti, Zr, Hf). Significantly, the determined zT value of p-type ZrCo1.33 Sn reaches 0.54 at 1000K, thanks to its high-power element and low thermal conductivity.Conclusion and Potential Impact” Our research anticipates distinct S-P Heusler semiconductors with remarkable thermoelectric abilities and clarifies the physical mechanism driving their development,” stated Zhuoyang Ti.Reference: “Bonding homes of Rubiks- cube-like Slater-Pauling Heusler semiconductors for thermoelectrics” by Zhuoyang Ti, Jianbo Zhu, Shuping Guo, Jingyu Li, Xiaobing Liu and Yongsheng Zhang, 15 November 2023, Physical Review B.DOI: 10.1103/ PhysRevB.108.195203.
By Weiwei Zhao and Zhuoyang Ti, Chinese Academy of Sciences (CAS) January 4, 2024Researchers have actually established Slater-Pauling (S-P) Heusler materials, resembling a Rubiks cube structure, with promising thermoelectric applications. These materials defy traditional semiconductor guidelines while keeping semiconductor habits. Credit: Chinese Academy of SciencesScientists have produced distinct Slater-Pauling Heusler products with semiconductor homes, offering considerable capacity in thermoelectric applications. Their research exposes these products unique electron redistribution and thermal properties.Recently, scientists from Hefei Institutes of Physical Science (HFIPS) of Chinese Academy of Sciences (CAS) created Slater-Pauling (S-P) Heusler products with an unique structure looking like a Rubiks cube. These products showed potential in thermoelectric applications due to their semiconductor-like properties.Unique Semiconductor Behavior” In standard semiconductor Heusler alloys, the variety of valence electrons follows a specific rule. These S-P Heusler substances defy this rule while still showing semiconductor habits,” stated Zhuoyang Ti, first author of the paper, “we effectively explained the underlying factors for this phenomena in this study.” These findings have been published in Physical Review B.Figure 1. Theoretically forecasted TiFe1.5 Sb and MCo1.33 Sn crystal structures and the arrangement of bases. Credit: Zhuoyang TiExploration of Off-Stoichiometry Heusler CompoundsSome off-stoichiometry Heusler substances have been forecasted to display semiconductor characteristics. However, the bonding behavior in these S-P semiconductors and the relationship in between their crystal structure and thermoelectric performance have actually remained unclear.In-Depth Research on Heusler SystemsIn this research, the group focused on 2 Heusler systems: Ti-Fe-Sb and M-Co-Sn (M = Ti, Zr, Hf). Within these 2 systems, they anticipated the thermodynamically steady TiFe1.5 Sb and MCo1.33 Sn S-P semiconductors.Figure 2. (a, b) Atom-resolved density of states (DOS) and crystal orbital Hamiltonian population (COHP) of TiFe1.5 Sb. (c, d) Schematic illustration of molecular orbital (MO) diagram in forming TiFe1.5 Sb. Credit: Zhuoyang TiUnderstanding the Unique PropertiesThe researchers even more described the factor behind the special properties of these compounds.Delving deeper, the scientists explained the special residential or commercial properties of these compounds. Beyond the acknowledged HH and FH local geometries, these S-P structures integrate defective-HH (DH) and defective-FH (DF) foundations. This is because of the partial occupation of Y atoms (Fe or Co) at the 4d Wyckoff site. An intriguing consequence of this is the development of 2nd- and third-order Rubiks cube patterns in TiFe1.5 Sb and MCo1.33 Sn, attributed to the regular stacking of these substructures.This distinct plan is type in redistributing electrons within the lattice, leading to the formation of a bandgap. It likewise minimizes the phonon Debye temperature level and boosts anharmonic vibrations, which in turn suppress lattice thermal conductivity. As an outcome, these materials exhibit lower thermal conductivities compared to conventional HH and FH substances. Notably, the computed zT value of p-type ZrCo1.33 Sn reaches 0.54 at 1000K, thanks to its high-power factor and low thermal conductivity.Conclusion and Potential Impact” Our research study anticipates distinct S-P Heusler semiconductors with remarkable thermoelectric capabilities and clarifies the physical system driving their emergence,” said Zhuoyang Ti.Reference: “Bonding properties of Rubiks- cube-like Slater-Pauling Heusler semiconductors for thermoelectrics” by Zhuoyang Ti, Jianbo Zhu, Shuping Guo, Jingyu Li, Xiaobing Liu and Yongsheng Zhang, 15 November 2023, Physical Review B.DOI: 10.1103/ PhysRevB.108.195203.
