Thermoelasticity of CaO from first principles

Liu, Zi‐Jiang; Qi, Jianhong; Guo, Yuxue; Chen, Qifeng; Cai, Ling-Cang; Yang, Xinling

doi:10.1088/1009-1963/16/2/035

Cited by 15 publications

(3 citation statements)

References 39 publications

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“…Nevertheless, the present study brings out an importance of the inherent temperature effect, such as creation of vacancy, to anharmonic properties like thermal expansion and thermal EOS. Based on the present examination and previous first principles study all based within the QHA [11,12], we conclude that the QHA is inadequate to account for the true anharmonism, particularly when T>>θ D . As a quantitative confirmation of this fact, we strongly believe that the study of temperature variation of thermo-elastic properties for divalent metal oxides ranging up to melting temperature is inevitable.…”

Section: Discussionmentioning

confidence: 49%

“…Present results with vacancy contribution are in excellent agreement with the experimental [10] findings. For comparison, previous DFT-QHA based results [11,12], and semi-empirical data due to Srivastava and Sinha [13] are also plotted in the figure . Though the semi-empirical results in Ref. [13] are close to the experimental results, their almost linear temperature dependence of β up to highest temperature is uncertain.…”

Section: Resultsmentioning

confidence: 99%

“…[12] (solid square), Ref. [11] (long-dashed line) and Ref. [13] (diamond), while experimental data (circles) are from [10].…”

Section: Resultsmentioning

confidence: 99%

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Thermal Properties of Divalent Metal Oxides: CaO as a Prototype

Bhatt

Thakore

Vyas

et al. 2013

SSP

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Commonly employed quasiharmonic approximation (QHA) is inadequate to account for intrinsic anharmonism such as phonon-phonon interaction, vacancy contribution, etc. Though anharmonic contributions are important at high temperatures and low pressure, complete ab initio calculations are scanty due largely to laborious computational requirements. Nevertheless, some simple semi-empirical schemes can be used effectively to incorporate the anharmonism. In this regards, in the present study we have proposed a simple computational scheme to include the effect of vacancy directly into the description within the mean-field potential approach, which calculates vibrational free energy of ions. Validity of the scheme is verified by taking calcium oxide as a test case. Equilibrium properties at (T,P) = (0,0) condition is obtained within the tight-binding second-moment approximation (TB-SMA), whose parameters were determined through first principles density functional theory. Kohn-Sham equations for core electrons were solved using ultrasoft plane-wave pseudopotential employing the generalized gradient approximation for exchange and correlation. Present findings for thermal expansion and high-T EOS clearly show perceptible improvement over the case when vacancy contribution was not included. Some related thermodynamic properties are also calculated and compared with the available experimental and theoretical data.

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Section: Discussionmentioning

confidence: 49%