First-principles study on the structural, elastic, electronic, optical and thermophysical properties of NaNO₃ and K-doped NaNO₃

Abstract

The present work represents the structural, electronic, elastic, and thermophysical properties of pure and K-doped NaNO3 obtained using DFT calculations. The estimated structural properties of NaNO3 correspond well with the existing reported values. Electronic characteristics such as band structure and density of statesof pure and doped NaNO3 are analyzed where the calculated band gaps for pure and K-doped NaNO3 are found to be 3.05 eV and 2.90 eV, respectively. The Berry–phase calculations carried out on both systems showed the existence of ferroelectric polarization, where an enhanced spontaneous polarization value of 36 μC/cm2 for K-doped NaNO3, as compared to 20 μC/cm2 for intrinsic NaNO3. The thermophysical properties such as bulk modulus (B0), Debye temperature (θD), and specific heat capacity (Cv) were calculated over a wide temperature range from 0K to 800 K. The linear optical properties namely the dielectric constant, refractive index, absorption coefficient, extinction coefficient and electron energy loss function are calculated in wide energy range from 0 to 30 eV and discussed in detail.