A SUPERCELL LMTO-ASA CALCULATION OF GROUND-STATE PROPERTIES OF Nb(C 1-x □ x )

The ground-state properties of Nb(C 1 -x □ x ) have been calculated by using a LDF-LM-TO-ASA supercell method. The calculation was performed by quadruple unit-cell such as Nb 4 C 3 □ 0 , Nb 4 C 3 □ 1 , Nb 4 C 2 □ 2 ,Nb 4 C 1 □ 3 and Nb 4 C 0 □ 4 . The equilibrium lattice constant a(x) , bulkmoduli B(x), Debye temperatures θ D (x) and heat of formation h (x) obtained from LM-TO calculation were combined with Bernoull's distribution. These results are in agreement with experimental data.