Stable structure of platinum carbides: A first principles investigation on the structure, elastic, electronic and phonon properties (original) (raw)
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Structural and Mechanical Properties of Platinum Carbide
Inorganic Chemistry, 2014
Platinum carbide (PtC) was synthesized under extreme conditions and considered as a potential candidate for superhard materials. However, the unsettled issue concerning the structural identification has impeded the full understanding of its physical and chemical properties. Here, we examine by first-principles calculations the crystal structure under high pressure and ideal strength along several high-symmetry directions under large deformation. The current calculations reveal that the zinc blende structure is the thermodynamically stable phase, and the simulated X-ray diffraction data are in excellent agreement with the experimental pattern. Further strain−stress calculations indicate that anomalous fluctuating behaviors of ideal strength occur in PtC. These results are expected to broaden our understanding of the structural and mechanical properties for other potential superhard materials formed by heavy transition metals and light elements.
Theoretical study of ground state and high-pressure phase of platinum carbide
Journal of Physics and Chemistry of Solids, 2008
We report local density-functional calculations using the full-potential linearized muffin-tin orbital method (FP-LMTO) for platinum carbide (PtC) in the, rock-salt (B1), zinc-blende (B3), wurtzite (B4), nickel-arsenide (B8) and PbO (B10) structures. The ground state properties such as the equilibrium lattice constant, elastic constants, the bulk modulus and its pressure derivative of PtC in these phases are determined and compared with available experimental and theoretical data.
The first principles study on PtC compound
Materials Chemistry and Physics, 2008
ABSTRACT We have studied structural, thermodynamic, elastic, and electronic properties of platinum carbide (PtC) in zinc-blende and rock-salt structures by performing ab initio calculations within the LDA approximations. Particularly, we have focused on the structural and the pressure dependence of elastic moduli and related quantities. The other basic key properties, such as the lattice constant, cohesive energy, the phase transition pressure, bulk modulus and its pressure derivative are also repeated and compared with the other available experimental and theoretical works.
Crystals
We investigated structure optimization, mechanical stability, electronic and bonding properties of the nanolaminate compounds Ti2PbC, Zr2PbC, and Hf2PbC using the first-principles calculations. These structures display nanolaminated edifices where MC layers are interleaved with Pb. The calculation of formation energies, elastic moduli and phonons reveal that all MAX phase systems are exothermic, and are intrinsically and dynamically stable at zero and under pressure. The mechanical and thermal properties are reported with fundamental insights. Results of bulk modulus and shear modulus show that the investigated compounds display a remarkable hardness. The elastic constants C11 and C33 rise more quickly with an increase in pressure than that of other elastic constants. Electronic and bonding properties are investigated through the calculation of electronic band structure, density of states, and charge densities.
Chinese Journal of Physics, 2017
The structural phase transformations of the PtN compound with a 1:1 stoichiometric ratio of Pt:N were investigated using the framework of density functional theory (DFT). The full potential linearized augmented plane wave (FP-LAPW) method within the generalized gradient (PBE-GGA) and the Engel-Vosko generalized gradient (EV-GGA) approximations were used. A comparative study of the experimental and theoretical results is provided on the structural properties of zinc-blende (ZB), rock-salt (RS), cesium chloride (CsCl), wurtzite (WZ), nickel arsenide (NiAs), lead monoxide (PbO), and tungsten carbide (WC) phases. The calculated band structure using the modified version of the Becke and Johnson (mBJ) exchange potential reveals the metallic character of the PtN compound. The present study also shows that the PtN compound crystallizes in the WZ phase under ambient conditions. The theoretical transition pressures from WZ to RS, NiAs, PbO, and CsCl transformations are found to be 9.441 GPa, 7.705 GPa, 18.345 GPa and 31.9 GPa, respectively, using the PBE-GGA method.
Solid State Communications, 2011
The structural, elastic and electronic properties of TiC, ZrC, HfC and TaC have been investigated by first-principles calculations using the plane-wave pseudopotential method. Different exchange–correlation functionals regarding the local density approximation and the PBE, RPBE and PW91 forms of generalized gradient approximation are taken into account. The NaCl-type cubic structures of TMC (TM=Ti, Zr, Hf and Ta) are optimized and confirmed to be mechanically stable. The elastic properties such as the elastic constants, bulk modulus, shear modulus, Young’s modulus and Poisson’s ratio of TMC are investigated, and the performances of LDA and GGA are discussed. The electronic density of state, electron charge density and Mulliken population analysis have been explored to discuss the electronic properties and bonding behaviors of TMC. The present calculation results compare satisfactorily with the experimental data and previous theoretical calculations.► Structural, elastic and electronic properties of TMC have been investigated. ► Performances of LDA and GGA are discussed for the structural and elastic properties. ► DOS, electron charge density and Mulliken population analysis have been explored. ► The bonding nature of TMC is a combination of covalent, ionic and metallic.
Solid State Communications, 2018
Ab-initio calculations based on density functional theory have been performed to study the structural, electronic, thermodynamic and mechanical properties of intermetallic compounds Pt 3 Sc and Pt 3 Y using the full-potential linearized augmented plane wave(FP-LAPW) method. The total energy calculations performed for L1 2 , D0 22 and D0 24 structures confirm the experimental phase stability. Using the generalized gradient approximation (GGA), the values of enthalpies formation are À1.23 eV/atom and À1.18 eV/atom for Pt 3 Sc and Pt 3 Y, respectively. The densities of states (DOS) spectra show the existence of a pseudo-gap at the Fermi level for both compounds which indicate the strong spd hybridization and directing covalent bonding. Furthermore, the density of states at the Fermi level N(E F), the electronic specific heat coefficient (γ ele) and the number of bonding electrons per atom are predicted in addition to the elastic constants (C 11 , C 12 and C 44). The shear modulus (G H), Young's modulus (E), Poisson's ratio (ν), anisotropy factor (A), ratio of B/G H and Cauchy pressure (C 12-C 44) are also estimated. These parameters show that the Pt 3 Sc and Pt 3 Y are ductile compounds. The thermodynamic properties were calculated using the quasi-harmonic Debye model to account for their lattice vibrations. In addition, the influence of the temperature and pressure was analyzed on the heat capacities (C p and C v), thermal expansion coefficient (α), Debye temperature (θ D) and Grüneisen parameter (γ).
NeuroQuantology, 2024
In this article, we examine the structural, electronic, and elastic characteristics of transition metal carbides ZnC and NbC as well as their ternary alloy ZnxNb1−xC (x =0, 0.25, 0.50 and 0.75, 1). Our analysis utilized a Generalized Gradient Approximation along with the modified Becke-Johnson potential (mBJ) using the Full Potential Linearized Augmented Plane Wave (FP-LAPW) approach. We calculated lattice parameters, bulk modulus, pressure derivative, and elastic constants. Additionally, we derived Young's modulus, shear modulus Poisson's ratio anisotropy factor from our obtained elastic constants. Furthermore, discussion is presented on total and partial densities of states as well as charge densities.
First-principles study of structural, elastic, and electronic properties of chromium carbides
Applied Physics Letters, 2008
The structural, elastic and electronic properties of Ti 2 InC and Ti 2 InN compounds have been calculated using the full-potential linear muffin-tin orbital (FP-LMTO) method. The exchange and correlation potential is treated by the local density approximation (LDA). The calculated ground state properties, including, lattice constants, internal parameters, bulk modulus and the pressure derivative of the bulk modulus are in reasonable agreement with the available data. The effect of pressure, up to 40 GPa, on the lattice constants and the internal parameters is also investigated. Using the total energy-strain technique, we have determined the elastic constants C ij , which have not been measured yet. The band structure and the density of states (DOS) show that both materials have a metallic character and Ti 2 InN is more conducting than Ti 2 InC. The analysis of the site and momentum projected densities shows that the bonding is achieved through a hybridization of Ti-atom d states with C (N)-atom p states. Otherwise, it has been shown that TiC and TiN bonds are stronger than Ti-In bonds.