Thermoelectric investigation of transition metal oxide <scp> NiO ₂ </scp> : A first principles study

Abstract

The structural, electronic, and thermoelectric transport properties of two-dimensional (2D) NiO2 are investigated with the help of combined density functional theory and semi-classical Boltzmann transport equations. Formation energy and phonon dispersion are in support of the chemical and dynamical stability of NiO2. Calculations reveal the semiconducting nature of the monolayer with indirect band-gap of 1.65 eV. Based on the electronic band structure, the variation of transport properties with chemical potential (μ) at different temperatures (300, 500, and 700 K) are explored. Elastic constant, deformation potential constants, and effective masses are calculated to obtain the exact value of relaxation time and mobility of charge carriers at different temperatures. The maximum value of Seebeck coefficient and electrical conductivity is −2674 μVK−1 and 9.92 × 105 Sm−1, respectively, while the peak value of electronic thermal conductivity is 7.22 Wm−1 K−2 leading to ZT of 0.506. The transport properties indicate that the monolayer can be used efficiently for collective response of transport properties.