First Principles Investigations on Ruthenium‐Based Semiconductors Heusler Alloys XRuTe (X = Ti, Zr, Hf) for Thermoelectric Applications

In this work, the structural, mechanical, electronic, and thermoelectric characteristics of Ru‐ based half Heusler alloys XRuTe (X = Ti, Zr, Hf) are thoroughly investigated from first‐principles calculations. These studies were carried out with the help of density functional theory (DFT) using the method of generalized gradient approximation and Boltzmann transport theory to understand their thermoelectric performance. The Structural analysis of these half‐Heusler alloys XRuTe (X = Ti, Zr, Hf) confirms that they are thermodynamically stable with negative formation energy and exhibit a cubic phase. According to electronic band structure studies, ZrRuTe and TiRuTe half‐Heusler alloys are semiconductors with a direct bandgap, but HfRuTe half‐Heusler alloy has a very narrow bandgap of 0.0017 eV. The thermoelectric parameters such as Seebeck Coefficient, electrical conductivity, and thermal conductivity are examined in the temperature range of 100–1200 K. The maximum figure of merit (ZT) is achieved under p‐type doping conditions, highlighting the potential of TiRuTe, ZrRuTe, and HfRuTe half‐Heusler alloy materials for high‐temperature thermoelectric applications.