Structural, electronic, elastic properties and chemical bonding in LaNi2P2 and LaNi2Ge2 from first principles

New ternary superconducting compound LaRu 2 As 2 : Physical properties from density functional theory calculations

“…The well-established Voight-Reuss-Hill (VRH) approximations validated in many metallic and insulating materials [25][26][27] Table 2 along with the results found in literature for La-based isostructural compounds [28]. The mechanical stability conditions for tetragonal crystals [29] are as follows: C 11 > 0, C 33 > 0, C 44 > 0, C 66 > 0, C 11 -C 12 > 0, C 11 + C 33 -2 C 13 > 0, 2(C 11 + C 12 ) + C 33 + 4 C 13 > 0.…”

“…These criteria are frequently used to identify the brittle material from ductile ones. [28] For describing the elastic behavior of solids, bulk and shear moduli are two important parameters. Fracture and plastic deformation are two essential issues related to solid materials.…”

“…The Debye temperature,  D , is determined by using one of the standard methods depending on the elastic moduli [50] Table 3. The values of v l , v t , v m , and  D found in literature [28] are calculated by using elastic moduli B and G within the Voigt approximation. Here we converted these values into aggregate values using Hill approximations [27].…”

The Electronic, Optical and Lattice Dynamical Properties of YIr2X2 (X=Si, Ge) Polymorphs: A DFT Study

“…To date, large variety of ternary intermetallic systems have been discovered and many of them remain subjects of intensive scientific interest [1]. The broad family of 122-type intermetallic with a tetragonal ThCr2Si2 structure demonstrates a remarkable range of physical and chemical properties [2]. These systems include the ternary disilicide YIr2Si2, for which two superconducting polymorphic forms exist: a low-temperature modification (LT) with a ThCr2Si2-type structure (Tc<2K) and high -temperature modification (HT) with a CaBe2Ge2type structure (Tc~2.8 K) [3].…”

“…There are only experimental [1] study and a few theoretical [2][3][4][5][6][7] studies dealing with the structural, elastic, and electronic properties of tetragonal ThCr2Si2 structure, particularly YIr2Si2, in the literature. Especially, Valiska et al have reported on existence of superconductivity in YIr2Si2 and LaIr2Si2 compounds in relation to crystal structure by experimental method [1].…”