Physical properties investigation of tetragonal Ba <i>T</i> ₂ P ₂ ( <i>T</i> = Ru, Pd)

Abstract The structural, thermal, electrical transport, and magnetic properties of ternary compounds Ba T 2 P 2 ( T = Ru, Pd) are reported together with electronic structure calculations. Our results show that BaRu 2 P 2 crystallizes in the layered tetragonal ThCr 2 Si 2 -type structure (space group I 4/ mmm ) whereas BaPd 2 P 2 adopts the primitive tetragonal CeMg 2 Si 2 -type structure (space group P 4/ mmm ). The combined experimental results and electronic structure calculations suggest metallic and diamagnetic ground states for both materials. Electrical transport measurements further indicate non-Fermi liquid behavior at low temperatures. Notably, BaRu 2 P 2 exhibits an anomalous feature in the magnetic susceptibility at T ∼ 260 K, similar to that observed in BaRu 2 As 2 . A comparison between the bare density of states obtained from electronic structure calculations and the experimentally estimated values suggests the presence of strong correlation effects in the material. Furthermore, the heat capacity of BaPd 2 P 2 , calculated using the full phonon dispersion relation, is in good agreement with the experimental data, particularly at low temperatures, highlighting the significant contribution of optical phonon branches to C p in this temperature range.