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Electronic, Mechanical and Thermal Properties of Binary Rare-earth Semiconducting Materials

Dheerendra Singh Yadav1 and D. V. Singh2

1Department of Physics, Ch. Charan Singh P. G. College Heonra (Saifai) Etawah-206001, U. P., INDIA. 2Department of Physics, S. V. College Aligarh, U. P., INDIA.


Using the modified dielectric theory of solids, the electronic, mechanical and thermal properties of many rare-earth mono-nitrides (LaN, CeN, PrN, NdN, SmN, GdN, TbN, DyN, HoN, ErN, TmN, YbN & LuN) are presented here The values of energy gaps such as homopolar gaps (Eh), heteropolar gaps (Ec) and average energy gaps (Ep in eV) were evaluated for these binary rare earth semiconducting materials with face centered cubic (FCC) NaCl-type structure. The derived values of average energy gap (Ep) are found to be in excellent agreement with the values obtained from the Penn model. Electronic polarizability was investigated using Chemla’s relation and the investigated values are shown to be in accordance with the results obtained from the Clausius–Mossotti relation. Phillips ionicity (fi) was evaluated and the obtained values were compared with the values obtained from Tubbs and Pauling’s ionicity model. The evaluated values of crystal ionicity were used to calculate the mechanical and thermal properties such as bulk-modulus (B in GPa) and heat of formation (-ΔHf in Kcal/mol) of these compounds. An excellent agreement has been found between calculated and experimental data as compared to other such theoretical findings. The results for bulk modulus (B) differ from experimental values by the following amounts LaN-0.87%, TbN-2.79%; and the results for Heat of formation (-ΔHf) differ from experimental values by the following amounts: LaN-0.49%, CeN-0.03%, PrN-0.90%, NdN-1.39%, SmN-0.35%, GdN-1.12%, TbN-0.51%, DyN-0.56%, HoN-0.03%, ErN-0.33%, TmN-0.33%, YbN-0.34 & LuN-0.57%.

Keywords : Electronic properties, Mechanical and Thermal properties, REN’s.