Diverse ratio of electronic and internal-strain piezoelectricity in half-Heusler semiconductor for the design of multifunctional piezoelectric devices

Half-Heusler (HH) semiconductors are promising for piezoelectric applications owing to their non-centrosymmetric structures and thermal stability, but the corresponding piezoelectric mechanisms and atomic-scale tunability remain elusive. This work addresses this gap by investigating non-centrosymmetric HH compounds via atomic substitution. Using first-principles calculations and lattice dynamics analysis, we quantify electronic and internal-strain piezoelectric contributions for 47 HH compounds with the F4¯3m space group, which exhibit remarkable diversity in the ratio of electronic and internal-strain piezoelectric contributions. Critically, atom substitution enables a smooth transition between electronic- and ionic-dominated piezoelectricity, a unique advantage over traditional single-mechanism piezoelectric materials. This tunability provides a unified platform, where the ratio of the two piezoelectric components becomes a key design parameter, bridging atomic-scale structure manipulation and macroscale functionality. Moreover, shear strain engineering demonstrates that piezoelectric performance of most HH materials decreases under strain, yet exceptions (e.g., SbVRu) highlight the potential of mode modulation for performance enhancement. This work not only uncovers the physical origin of HH piezoelectricity but also establishes a framework for strain-controlled multifunctional devices.