The thermoelectric properties of novel two-dimensional semiconductor ZrNBr alloyed with Fluorine: A DFT+U survey

Abstract

In this survey, the thermoelectric properties of novel two-dimensional transition metal halide (ZrNBr) alloyed with Fluorine (F) in the replacement of Br atoms (with x = 0.5) have been studied. The density functional theory along with Hubbard’s potential has been used to study the density of states, the Seebeck coefficient, electrical conductivity, the electronic contribution of thermal conductivity, and the thermoelectric power factor. The dynamic and structural stability of the compounds has been proven by cohesive energy and phonon calculation results. By considering Hubbard’s potential of 3 eV the energy band gap of the electronic density of states has been enlarged to values of 2.73, and 2.7 eV for pure ZrNBr, and ZrNBr0.5F0.5, respectively. Moreover, the largest values of the thermoelectric power factor at room temperature (300 K) and without considering Hubbard’s potential were 29.12 × 1016 and 101 × 1016μW/m K2 s and at the negative chemical potential for pure ZrNBr, and ZrNBr0.5F0.5, respectively. While considering Hubbard’s potential, the largest peaks at 300 K were 26.42 × 1016μW/m K2 s (at positive chemical potential) and 41.41 × 1016μW/m K2 s (at negative chemical potential), for pure ZrNBr, and ZrNBr0.5F0.5, respectively. These values are in the ranges of the results for materials which are potential candidates for thermoelectric applications.