Controlling electronic transport properties in Half-Heusler compound of Zr0.5Hf0.5NiSn through isovalent and aliovalent substitutions

Half-Heusler (HH) semiconductors usually considered as promising p-type electronic materials, an effective n-type doping in HH compounds remains unexplored, demanding further exploration of the fundamental understanding to design electron-rich semiconductors. In this regard, we systematically investigate the electronic and carrier transport properties of the isovalent and aliovalent substituted Zr0.5Hf0.5NiSn HH compounds using first-principles-based density functional theory (DFT) combined with solving the Boltzmann transport equation (BTE). The electronic correlation and spin-orbit coupling (SOC) are incorporated while studying the electronic band dispersion and transport properties. To capture the strong on-site electron-electron interactions arising from the orbitals and to accurately predict the experimental band gap, we incorporate Hubbard U corrections in the electronic structure calculations. We demonstrate that Hubbard U correction plays a significant role in estimating experimental bandgap, useful to determine accurately carrier concentration and then electrical conductivity. The present work highlights the potential electronic performance of the isovalent and aliovalent substituted Zr0.5Hf0.5NiSn systems, identifying aliovalent substitution as an effective n-type dopant to optimize carrier mobility. Our findings reveal a significant enhancement in electrical conductivity for both electrons and holes in the aliovalent substituted Zr0.5Hf0.5NiSn, reaching 84.64× 102 and 12.66× 102 S/cm, respectively, compared to 1.72× 102 and 0.43×102 S/cm in the pristine compound. This suggesting that aliovalent substituted HH system is a highly promising candidate for advanced electronics and transport applications. These results not only aid in understanding the fundamental physical properties of the materials but also provide theoretical support to guide the dopant selection and experimental optimization of the n-type HH semiconductors for their advanced electronic applications.