Electronic and Thermoelectric Transport Properties of CaAgP from First Principles

Abstract

Recent experimental and theoretical progress on semiconducting CaAgP prompted us to investigate in detail the electrical and thermal transport properties of this hexagonal pnictide, using first-principles calculations based on the density functional theory. In contrast to using a standard generalized gradient approximation, employing a hybrid Heyd–Scuseria–Ernzerhof functional yields its semiconducting nature, in agreement with the experimental observation with a bandgap of ∼0.15 eV. The narrow band gap semiconductor CaAgP, which under negative (chemical) pressure has been shown to turn into a nodal-line semimetal, is found to be dynamically stable, with a gapped electronic band structure when a hybrid functional is used. This is in an attractive range for applications in thermoelectric devices, and we have determined the lattice and electronic conductivity as a function of doping, which indeed predicts a promising thermoelectric performance, particularly for p-doped CaAgP.