First principles computation of structural, electronic, magnetic and mechanical properties of new lithium based half Heusler alloys

First principles calculations have been accomplished for structural, electronic, magnetic and mechanical properties of half Heusler (HH) LiYZ (<mml:mstyle>Y</mml:mstyle> = <mml:mstyle>Ru</mml:mstyle>, Rh and <mml:mstyle>Z</mml:mstyle> = <mml:mstyle>As</mml:mstyle>, Se, Te, Sb) alloys using the density functional theory (DFT) within full potential-linearized augmented plane wave (FP-LAPW) method. To calculate the physical properties, Perdew-Burke-Ernzerhof (PBE) potential and generalized gradient approximation (GGA) are employed. The calculations are accomplished for three phases to obtain the most stable phase. The results of these calculations revealed that Type-III is the most stable of LiRhSe and LiRhSb, Type-I of LiRhAs, LiRhTe, LiRuAs, LiRuSb, LiRuSe and LiRuTe alloys. The structural optimization is obtained by plotting the graphs between minimum volume and the lowest energy of all considered alloys. The results of electronic properties including density of states (DOS) and band structures are also presented. The obtained total magnetic moment (MM) is negative for LiRhSb, LiRuSb, LiRhTe, LiRuTe, while it is positive for LiRhSe, LiRuSe, LiRhAs, LiRuAs Heusler alloys (HAs). To determine the mechanical stability, several parameters such as Poisson's ratio, Pugh's ratio, Lame's coefficient, anisotropy factor, Kleinman parameter, Young's modulus, Bulk modulus and Cauchy pressure are calculated and discussed in detail.