The density functional theory within the generalized gradient approximation (GGA) and local spin ... more The density functional theory within the generalized gradient approximation (GGA) and local spin density approximation (LSDA) has been used to calculate the structural and electronic properties of gadolinium monoarsenide GdAs at ambient as well as at high pressure. At ambient pressure, GdAs possess NaCl-type structure while magnetically it is stable in anti-ferromagnetic (AFM) state and is found to undergo from
ABSTRACT A theoretical study on structural, electronic, magnetic and thermal properties of actini... more ABSTRACT A theoretical study on structural, electronic, magnetic and thermal properties of actinide monocarbides AnCs (An= Np and Cm), which crystallize in NaCl-type structure, has been performed using self consistent tight binding linear muffin tin orbital (TB-LMTO) method at ambient as well as at high pressure. Both non-spin and spin polarized calculations have been performed to check the magnetic stability. We observe that both the compounds are metallic in nature and ferro-magnetically stable at ambient pressure. The calculated ground state properties such as lattice constants and bulk modulus are compared with the available results. The Debye temperature is also estimated for the first time.
A theoretical study of structural, electronic, elastic, thermal and mechanical properties of nonm... more A theoretical study of structural, electronic, elastic, thermal and mechanical properties of nonmagnetic intermetallics YM (M=Cu, Zn and Ag), which crystallize in CsCl-type structure, is performed using first principles density functional theory based on full potential linearized augmented plane wave (FP-LAPW) method. The calculations are carried out within the generalized gradient approximation (GGA) for the exchange correlation potential. The calculated ground state properties such as lattice constants, bulk modulus and elastic constants agree well with the experiment. From energy dispersion curves, it is found that these compounds are metallic in nature. The ductility of these intermetallics is determined by calculating the bulk to shear ratio B/GH. The calculated results indicate that YAg is the most ductile amongst the present YM compounds. The results obtained are compared with the available experimental and theoretical results. The mechanical and thermal properties are predicted from the calculated values of elastic constants.
The structural and elastic properties of praseodymium monochalcogenides (PrX: X = S, Se, Te) and ... more The structural and elastic properties of praseodymium monochalcogenides (PrX: X = S, Se, Te) and monopnictides (PrY: Y = P, As, Sb, Bi) with NaCl-type structure have been investigated by using an interionic potential theory with necessary modification to include the effect of Coulomb screening due to the delocalized f-electrons of rare earth ion. The calculations are done at ambient as well as at high pressure. The structure of the high pressure phase of PrX compounds is CsCl-type while all the PrY compounds have been found to undergo from their initial NaCl-type structure to high pressure body centered tetragonal (BCT) structure, which can be seen as the distorted CsCl-type with c/a ratio ≈ 0.82–0.87. The calculated transition pressures are in good agreement with the experimental results. The elastic properties like second-order elastic constants for PrX, Y compounds are calculated for the first time. The nature of the bonding is also predicted by calculating the distance between the ions with the increasing pressure.
The structural, elastic and thermal properties of three heavy monoantimonides of holmium, erbium ... more The structural, elastic and thermal properties of three heavy monoantimonides of holmium, erbium and thulium (LnSb, Ln=Ho, Er and Tm) have been investigated theoretically by using an interionic potential theory consisting of long-range Coulomb, short-range repulsive and van der Waal’s (vdW) interactions. These compounds exhibit first-order crystallographic phase transition from their initial NaCl-type structure to CsCl-type structure at pressures 27, 33.2 and 29.8 GPa for HoSb, ErSb and TmSb, respectively. The values of elastic constants and Debye temperatures as a function of pressure are also reported. The elastic properties such as Young modulus (E), Shear modulus (G), Poisson ratio (υ) and anisotropic ratio (A) in an NaCl-type structure are also predicted.
The pressure induced structural phase transition and elastic properties of lutatium monopnictides... more The pressure induced structural phase transition and elastic properties of lutatium monopnictides LuX (X = N, P, Bi) have been studied using the first principles density functional theory within the generalized gradient approximation. The present work indicates that there is a structural phase transition from their ambient NaCl- (B1) structure to CsCl- (B2) structure at 299, 105 and 27 GPa along with the volume collapse of 4.7, 6.8 and 7.0%, respectively. Structural parameters like lattice constant (a0), bulk modulus (B) and pressure derivatives of bulk moduli (B') are presented. We also report the second order elastic constants for these compounds.
The density functional theory within the generalized gradient approximation (GGA) and local spin ... more The density functional theory within the generalized gradient approximation (GGA) and local spin density approximation (LSDA) has been used to calculate the structural and electronic properties of gadolinium monoarsenide GdAs at ambient as well as at high pressure. At ambient pressure, GdAs possess NaCl-type structure while magnetically it is stable in anti-ferromagnetic (AFM) state and is found to undergo from
ABSTRACT A theoretical study on structural, electronic, magnetic and thermal properties of actini... more ABSTRACT A theoretical study on structural, electronic, magnetic and thermal properties of actinide monocarbides AnCs (An= Np and Cm), which crystallize in NaCl-type structure, has been performed using self consistent tight binding linear muffin tin orbital (TB-LMTO) method at ambient as well as at high pressure. Both non-spin and spin polarized calculations have been performed to check the magnetic stability. We observe that both the compounds are metallic in nature and ferro-magnetically stable at ambient pressure. The calculated ground state properties such as lattice constants and bulk modulus are compared with the available results. The Debye temperature is also estimated for the first time.
A theoretical study of structural, electronic, elastic, thermal and mechanical properties of nonm... more A theoretical study of structural, electronic, elastic, thermal and mechanical properties of nonmagnetic intermetallics YM (M=Cu, Zn and Ag), which crystallize in CsCl-type structure, is performed using first principles density functional theory based on full potential linearized augmented plane wave (FP-LAPW) method. The calculations are carried out within the generalized gradient approximation (GGA) for the exchange correlation potential. The calculated ground state properties such as lattice constants, bulk modulus and elastic constants agree well with the experiment. From energy dispersion curves, it is found that these compounds are metallic in nature. The ductility of these intermetallics is determined by calculating the bulk to shear ratio B/GH. The calculated results indicate that YAg is the most ductile amongst the present YM compounds. The results obtained are compared with the available experimental and theoretical results. The mechanical and thermal properties are predicted from the calculated values of elastic constants.
The structural and elastic properties of praseodymium monochalcogenides (PrX: X = S, Se, Te) and ... more The structural and elastic properties of praseodymium monochalcogenides (PrX: X = S, Se, Te) and monopnictides (PrY: Y = P, As, Sb, Bi) with NaCl-type structure have been investigated by using an interionic potential theory with necessary modification to include the effect of Coulomb screening due to the delocalized f-electrons of rare earth ion. The calculations are done at ambient as well as at high pressure. The structure of the high pressure phase of PrX compounds is CsCl-type while all the PrY compounds have been found to undergo from their initial NaCl-type structure to high pressure body centered tetragonal (BCT) structure, which can be seen as the distorted CsCl-type with c/a ratio ≈ 0.82–0.87. The calculated transition pressures are in good agreement with the experimental results. The elastic properties like second-order elastic constants for PrX, Y compounds are calculated for the first time. The nature of the bonding is also predicted by calculating the distance between the ions with the increasing pressure.
The structural, elastic and thermal properties of three heavy monoantimonides of holmium, erbium ... more The structural, elastic and thermal properties of three heavy monoantimonides of holmium, erbium and thulium (LnSb, Ln=Ho, Er and Tm) have been investigated theoretically by using an interionic potential theory consisting of long-range Coulomb, short-range repulsive and van der Waal’s (vdW) interactions. These compounds exhibit first-order crystallographic phase transition from their initial NaCl-type structure to CsCl-type structure at pressures 27, 33.2 and 29.8 GPa for HoSb, ErSb and TmSb, respectively. The values of elastic constants and Debye temperatures as a function of pressure are also reported. The elastic properties such as Young modulus (E), Shear modulus (G), Poisson ratio (υ) and anisotropic ratio (A) in an NaCl-type structure are also predicted.
The pressure induced structural phase transition and elastic properties of lutatium monopnictides... more The pressure induced structural phase transition and elastic properties of lutatium monopnictides LuX (X = N, P, Bi) have been studied using the first principles density functional theory within the generalized gradient approximation. The present work indicates that there is a structural phase transition from their ambient NaCl- (B1) structure to CsCl- (B2) structure at 299, 105 and 27 GPa along with the volume collapse of 4.7, 6.8 and 7.0%, respectively. Structural parameters like lattice constant (a0), bulk modulus (B) and pressure derivatives of bulk moduli (B') are presented. We also report the second order elastic constants for these compounds.
Uploads