<i>Ab initio</i>up to the melting point: Anharmonicity and vacancies in aluminum

Grabowski, Blazej; Ismer, Lars; Hickel, Tilmann; Neugebauer, Jörg

doi:10.1103/physrevb.79.134106

Cited by 277 publications

(291 citation statements)

References 62 publications

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“…Given the fact that aluminum has been one of the most widely characterized and simulated metals 2,[4][5][6][7][8][9][10][11][12] , these results are rather surprising. However, it is important to note that the accurate determination of elastic constants through resonance techniques is far from trivial 13 , and the actual results are subject to non-negligible degrees of interpretation.…”

Section: Introductionmentioning

confidence: 63%

Finite-temperature elasticity of fcc Al: Atomistic simulations and ultrasonic measurements

et al. 2011

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Though not very often, in literature there are cases where discrepancies exist in temperature dependence of elastic constants of materials. A particular example of this case is the behavior of C 12 coefficient of a simple metal, aluminum. Here, we attempt to provide insight into various contributions to temperature-dependence in elastic properties by investigating the thermo-elastic properties of fcc aluminum as a function of temperature through the use of two computational techniques and experiments. First, ab initio calculations based on density functional theory (DFT) are used in combination with quasi-harmonic theory to calculate the elastic constants at finite temperatures through a strain-free energy approach. Molecular dynamics (MD) calculations using tight-binding potentials are then used to extract the elastic constants through a fluctuation-based formalism. Through this dynamic approach, the different contributions (Born, kinetic and stress fluctuations) to the elastic constants are isolated and the underlying physical basis for the observed thermally-induced softening is elucidated. The two approaches are then used to shed light on the relatively large discrepancies in the reported temperature dependence of the elastic constants of fcc aluminum. Finally, the polycrystalline elastic constants (and their temperature dependence) of fcc aluminum are determined using Resonant Ultrasound Spectroscopy (RUS) and compared to previously published data as well as the atomistic calculations performed in this work.

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Section: Introductionmentioning

confidence: 63%

Finite-temperature elasticity of fcc Al: Atomistic simulations and ultrasonic measurements

et al. 2011

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“…23 This computational method has shown outstanding efficiency and reliability for the calculation of various physical properties and structural transformations of simple and complex materials. 24 All considered compounds were calculated the same way. The energy cutoff was set to 400 eV.…”

Section: First-principles Calculationsmentioning

confidence: 99%

High-pressure structural behavior of large-void CoSn-type intermetallics: Experiments and first-principles calculations

et al. 2008

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The high-pressure structural behavior of the binary intermetallic compounds CoSn, FeSn, and NiIn with the peculiar void containing CoSn ͑B35͒-type structure has been studied by means of room-temperature diamond anvil cell and high-temperature multianvil experiments, as well as by first-principles calculations. All three compounds remain structurally stable at pressures up to at least 25 GPa, whereas first-principles calculations predict high-pressure structural changes below 20 GPa. A plausible explanation for the discrepancy is that at room temperature, a sizable activation barrier inhibits kinetically the transformation into more close-packed polymorphs. It is supported by our experiments at temperatures around 1000°C and a pressure of 10 GPa. At these conditions, NiIn transforms into the temperature-quenchable stoichiometric CsCl-type high-pressure phase, which has been predicted in our first-principles calculations. However, CoSn and FeSn decompose into a mixture of compounds richer and poorer in tin, respectively. Nevertheless, it might be possible that lower temperatures and higher pressures may afford theoretically predicted polymorphs. In particular, a phase transformation to the FeSi-type structure predicted for CoSn is of interest as materials with the FeSi-type structure are known for unusual thermal and transport properties.

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“…For that purpose, we calculate the dynamical matrix in Eq. (14) at various electronic temperatures and volumes. We include also the T el =0 K calculation by utilizing the Methfessel-Paxton scheme.…”

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confidence: 99%

“…In Ref. [14], the actual influence of T el on phonons and the resulting quasiharmonic free energy has been investigated. Ref.…”

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confidence: 99%

Temperature-driven phase transitions from first principles including all relevant excitations: The fcc-to-bcc transition in Ca

et al. 2011

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Ab initioup to the melting point: Anharmonicity and vacancies in aluminum

Cited by 277 publications

References 62 publications

Finite-temperature elasticity of fcc Al: Atomistic simulations and ultrasonic measurements

Finite-temperature elasticity of fcc Al: Atomistic simulations and ultrasonic measurements

High-pressure structural behavior of large-void CoSn-type intermetallics: Experiments and first-principles calculations

Temperature-driven phase transitions from first principles including all relevant excitations: The fcc-to-bcc transition in Ca

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