Structural Electronic and Thermoelectric Properties of CuGe2P3 Ternary Compound in Trigonal Phase Promising for Electronic Applications

This study examines the structural, electronic, and thermoelectric properties of trigonal-phase copper germanium phosphide (CuGe2P3) using density functional theory (DFT) calculations. The bulk modulus is 68.98 GPa with a pressure derivative of 4.53, obtained from the Birch-Murnaghan equation of state based on energy-volume data. This is lower than the 86.7 GPa reported for the disordered zincblende phase, indicating significant structural differences. Thermoelectric transport properties were evaluated at 100, 300, and 500 K. At 100 K, strong p-type transport with high Seebeck coefficients was observed, highlighting pronounced low-temperature electronic sensitivity. Using a representative lattice thermal conductivity, the estimated figure of merit zT reaches similar to 0.29 at 500 K, suggesting moderate thermoelectric performance. These results demonstrate that CuGe2P3 combines favorable structural stability with promising transport behavior, making it a potential candidate for mid-temperature thermoelectric applications.