Ab-initio studies of some rare-earth borides: CeB₂, PrB₂, NdB₂, and PmB₂

Abstract

Ab-initio studies of some rare-earth borides: CeB 2 ,P rB 2 ,NdB 2 ,a nd PmB 2The structural,mechanical and thermalproperties of CeB 2 , PrB 2, NdB 2 ,and PmB 2 compounds in hexagonal AlB 2 -type (P6/mmm) and ReB 2 -type structures (P6 3 /mmc) are investigated usingd ensity functional theory. The results indicate that those compounds with hexagonal AlB 2 structure are the most stablea mong the considered structures. The mechanical properties are calculated according to the elastic constants by means of the Voigt-Reuss-Hill averaging scheme. The temperature dependence of various quantities such bulkmodulus, Debye temperature, thermalexpansion, heat capacity, and Grüneisen parameter have been analyzed using the quasi-harmonicDebye model.