Pt-induced semimetallic transport and enhanced thermoelectric response in the half-Heusler alloy YNi_{0.5}Pt_{0.5}Bi
Year: 2026
Type: preprint
Abstract: Half-Heusler alloys provide a versatile platform for tuning electronic and thermal transport through chemical substitution. Here, we investigate the thermoelectric and magnetotransport properties of spark-plasma-sintered YNi_{0.5}Pt_{0.5}Bi. Partial substitution of Ni by Pt drives YNiBi toward semimetallic transport, characterized by hole-dominated conduction, a low Hall carrier concentration of $\mathrm{1.9 \times 10^{19} cm^{-3}}$, and a sizeable nonsaturating magnetoresistance of 18$\%$ at 300 K under 14 T. Compared with YNiBi, Pt alloying increases the room-temperature Seebeck coefficient from approximately 90 to 130 $\mathrm{μV K^{-1}}$, while reducing the thermal conductivity to 3.15 $\mathrm{W m^{-1} K^{-1}}$. Single-parabolic-band analysis indicates an enhanced carrier effective mass, resulting in a room-temperature power factor of 13.7 $\mathrm{μW cm^{-1} K^{-2}}$ and a figure of merit ($zT$= 0.13). First-principles calculations further show a Pt-induced closing of the electronic band gap and a low density of states near the Fermi level, consistent with the experimentally observed semimetal-like transport. These results demonstrate that Ni/Pt alloying provides an effective route for simultaneously tuning the electronic, magnetotransport, and thermoelectric properties of YNiBi-based half-Heusler compounds.
Source: arXiv (Cornell University)
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funders: Arthritis National Research Foundation, National Research Foundation, Department of Science and Technology, Ministry of Science and Technology, India, Defence Research and Development Organisation, Max-Planck-Gesellschaft, Ministry of Education, India, Indian Institute of Technology Delhi, Aeronautics Research and Development Board, Science and Engineering Research Board, Institute for Materials Research, Tohoku University
OpenAlex ID: W7222402653