A first-principles prediction on the structural, electronic, elastic, phonon, and transport properties of BaSiN₂

This first-principles research systematically investigates the transport properties of orthorhombic BaSiN₂ with space group C_mca (No. 64), as well as its structural, electronic, elastic, and vibrational behavior. To verify the mechanical stability of BaSiN₂, Born criteria were traditionally used. Then, by utilizing the computed elastic constants, the anisotropic shear factors and Poisson's ratio were obtained along with the two prominent parameters of shear modulus and Young's modulus. The electronic band structure has shown the semiconducting nature of this compound with a band gap of 2.83 eV. Moreover, the semiclassical Boltzmann transport theory has been applied to analyze the thermoelectric character of BaSiN₂. Thus, some crucial transport properties were presented as a function of chemical potential and temperature, such as Seebeck coefficient (S), figure of merit (ZT), electrical (σ) and electronic–thermal (κ_e) conductivities, and power factor (PF). Accordingly, p-type BaSiN₂ has a high PF and low thermal conductivity, which could give this material great potential for thermoelectric applications. The calculated maximum ZTe value is ∼1, and the predicted maximum ZT value is ~ 0.77 at 900 K. (author)