Ab Initio Study of Thermoelectric Transport Properties of Zintl Phase Nitride Ca ₂ ZnN ₂

The growing demand for alternative energy solutions has driven interest in thermoelectric materials for waste heat recovery. Zintl phases are promising thermoelectric candidates, yet the transport properties of Ca 2 ZnN 2 remain largely unexplored. In this work, we combine density functional theory and semiclassical Boltzmann transport calculations to predict the intrinsic thermoelectric properties of Ca 2 ZnN 2 . The compound crystallizes in a tetragonal structure and exhibits intrinsic p‐type behavior, with high electrical conductivity ( σ = 1.63 × 10 4 S cm) −1 and hole mobility of ( μ h ≈ 10 cm 2 V −1 s) −1 at 300 K. Polaroptical phonon scattering dominates carrier relaxation, yielding lifetimes around 10 −15 s. The lattice thermal conductivity is relatively large ( k L = 14.0 W m −1 K −1 for p‐type and 13.0 W m −1 K −1 for n‐type), resulting in modest room‐temperature figures of merit: ZT = 0.017 (p‐type) and ZT = 0.018 (n‐type). However, ZT increases with temperature and carrier concentration, reaching 0.07 (p‐type) and 0.08 (n‐type) at 500 K for n = 1 × 10 20 cm −3 . Notably, p‐type doping benefits from higher mobility and power factor despite n‐type having larger Seebeck coefficients, making Ca 2 ZnN 2 a promising candidate for p‐type thermoelectric applications.