Structural, electronic and thermoelectric properties of boron phosphorous nitride B2PN via first principles study

Abstract

A theoretical study of monolayer boron phosphorous nitride (B₂PN) is performed to explore its electronic and thermoelectric properties. The thermodynamic stability is determined by the formation energy of a monolayer. The dynamic stability is obtained from the phonon dispersion curve. We performed an AMID simulation to ensure the thermal stability and found that our material is thermally stable at 700 K. The system possesses direct band gaps of 0.25 eV and 0.4 eV with Perdew–Burke–Ernzerhof (PBE) and hybrid functional (HSE), respectively. The Seebeck coefficient is found to be the same in both directions, and the maximum value is 1.55 mV K⁻¹. The relaxation time is found to be longer for the hole-doped system than the electron-doped system. It is observed that electrical conductivity is greater for hole-doped system in both directions, and a similar trend is observed for electronic thermal conductivity. We found that the lattice thermal conductivity of our systems is anisotropic. The lattice thermal conductivity along the Y-direction is greater than that in the X-direction. The calculation performed for the figure of merit (ZT) reveals that the system has a high ZT of 1.14 for a hole-doped system. The figure of merit makes the system a promising candidate for potential thermoelectric device applications.