This study employs first-principles density functional theory (DFT) to systematically investigate the work function, mechanical properties, and thermodynamic performance of (La 1-x-y Pr x Ba y )B 6 alloys. The calculations reveal that the work function exhibits strong composition dependence and pronounced non-monotonic behavior. Ba substitution effectively reduces the work function, yielding values as low as 1.79 eV (La 0.125 Ba 0.625 Pr 0.25 B 6 ), whereas Pr mainly introduces local fluctuations through electronic effects. Mechanical analysis indicates that Ba doping significantly reduces elastic moduli, leading to lattice softening, while Pr tends to enhance ductility as reflected by increasing ratio B/G and Cauchy pressure. However, all compositions remain brittle according to the ratio B/G and Poisson’s ratio. The negative Cauchy pressure suggests a strong directional bonding contribution, while the PDOS and Bader charge analyses further reveal mixed ionic-covalent-metallic bonding characteristics. Thermodynamic properties show that the Debye temperature and melting point slightly decrease with increasing Ba content, indicating reduced thermal stability. These findings suggest that (La 1-x-y Pr x Ba y )B 6 alloys are promising candidates for Cs-free PG materials.
H et al. (Mon,) studied this question.