First-principle calculations of the bulk properties of 4d transition metal carbides and nitrides in the rocksalt, zincblende and wurtzite structures

Korir, K.K.; Amolo, George; Makau, Nicholas; Joubert, Daniel P.

doi:10.1016/j.diamond.2010.11.021

Cited by 68 publications

(22 citation statements)

References 32 publications

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“…The optimized lattice constants a, equilibrium volume V 0 , bulk modulus B, and first derivative of the bulk modulus with pressure B 0 at zero pressure are listed in Table 2. It is found that our results are in good agreement with the available experimental data [26] and previous theoretical results [13,14,25].…”

Section: 3supporting

confidence: 95%

Phase transition, elastic and thermodynamical properties of TcC under high pressure from first-principles calculations

Yang-Chun

Zhu

Hao

et al. 2014

Phys. Status Solidi B

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Phase transition, elastic and thermodynamical properties of technetium monocarbide (TcC) in the WC, NiAs, NaCl, CsCl, and ZnS structures have been studied by full-potential linearized augmented-plane-wave (FP-LAPW) theory. From the enthalpy difference between the five structures, we predict that the structural phase transition from WC-type structure to CsCl-type structure occurs at ca. 411.4 GPa. Meanwhile, it is found that the NiAs, NaCl, and ZnS types are not stable phases in whole pressure ranges considered. In particular, for the first time we calculate the elastic properties and phase transition of TcC under high pressures. For WC TcC and CsCl TcC structures, the elastic constants, bulk modulus, shear modulus, and Young's modulus are predicted to increase monotonically with increasing pressure. The Vickers hardness of TcC under high pressure is estimated. The brittle-ductile behavior of TcC has been obtained by Pugh's criteria. Finally, the Debye temperature, isochoric heat capacity and thermal expansion coefficient are predicted by the quasiharmonic Debye model method.

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Section: 3supporting

confidence: 95%

Phase transition, elastic and thermodynamical properties of TcC under high pressure from first-principles calculations

Yang-Chun

Zhu

Hao

et al. 2014

Phys. Status Solidi B

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“…The structural and elastic properties of 4d transition metal carbides have been studied by Korir et al 19 through ab initio calculations. Table 2 shows the values of the lattice constants and bulk moduli of MC (M = Y, Zr, Nb, and Rh) phases in the rocksalt structure (Fm-3m, No.…”

Section: Resultsmentioning

confidence: 99%

Effect of Valence Electron Concentration on Elastic Properties of 4d Transition Metal Carbides MC (M = Y, Zr, Nb, and Rh)

Kang

2013

Bulletin of the Korean Chemical Society

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The electronic structure and elastic properties of the 4d transition metal carbides MC (M = Y, Zr, Nb, Rh) were studied by means of extended Hückel tight-binding band electronic structure calculations. As the valence electron population of M increases, the bulk modulus of the MC compounds in the rocksalt structure does not increase monotonically. The dominant covalent bonding in these compounds is found to be M-C bonding, which mainly arises from the interaction between M 4d and C 2p orbitals. The bonding characteristics between M and C atoms affecting the variation of the bulk modulus can be understood on the basis of their electronic structure. The increasing bulk modulus from YC to NbC is associated with stronger interactions between M 4d and C 2p orbitals and the successive filling of M 4d-C 2p bonding states. The decreased bulk modulus for RhC is related to the partial occupation of Rh-C antibonding states.

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“…[30] and [31], and a = 4.70 to 4.72Å for GGA, Refs. [30][31][32][33][34]). From the quasiharmonic calculations, the thermal properties were found to depend strongly on the choice of exchange correlation functional.…”

Section: B Resultsmentioning

confidence: 99%

Improved method of calculatingab initiohigh-temperature thermodynamic properties with application to ZrC

Duff¹,

Davey²,

Korbmacher

et al. 2015

Phys. Rev. B

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Thermodynamic properties of ZrC are calculated up to the melting point (T melt ≈ 3700 K), using density functional theory (DFT) to obtain the fully anharmonic vibrational contribution, and including electronic excitations. A significant improvement is found in comparison to results calculated within the quasiharmonic approximation. The calculated thermal expansion is in better agreement with experiment and the heat capacity reproduces rather closely a CALPHAD estimate. The calculations are presented as an application of a development of the upsampled thermodynamic integration using Langevin dynamics (UP-TILD) approach. This development, referred to here as two-stage upsampled thermodynamic integration using Langevin dynamics (TU-TILD), is the inclusion of tailored interatomic potentials to characterize an intermediate reference state of anharmonic vibrations on a two-stage path of thermodynamic integration between the original DFT quasiharmonic free energy and the fully anharmonic DFT free energy. This approach greatly accelerates the convergence of the calculation, giving a factor of improvement in efficiency of ∼50 in the present case compared to the original UP-TILD approach, and it can be applied to a wide range of materials.

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First-principle calculations of the bulk properties of 4d transition metal carbides and nitrides in the rocksalt, zincblende and wurtzite structures

Cited by 68 publications

References 32 publications

Phase transition, elastic and thermodynamical properties of TcC under high pressure from first-principles calculations

Phase transition, elastic and thermodynamical properties of TcC under high pressure from first-principles calculations

Effect of Valence Electron Concentration on Elastic Properties of 4d Transition Metal Carbides MC (M = Y, Zr, Nb, and Rh)

Improved method of calculatingab initiohigh-temperature thermodynamic properties with application to ZrC

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