Dynamical simulations of an electronically induced solid-solid phase transformation in tungsten

Murphy, Samuel T.; Daraszewicz, Szymon L.; Giret, Yvelin; Watkins, Matthew; Shluger, Alexander L.; Tanimura, Katsumi; Duffy, Dorothy M.

doi:10.1103/physrevb.92.134110

Cited by 47 publications

(39 citation statements)

References 67 publications

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“…Theoretical studies have predicted that bcc tungsten becomes thermodynamically unstable with respect to close-packed fcc and hcp phases at extreme pressures 57 and under the conditions of strong electronic excitation during laser irradiation 81 , for which a T e -dependent interatomic potential was developed to study the transition 18 . To the authors' knowledge, fcc tungsten has only been observed in thin films formed by sputter deposition between 200 and 400 • C on glass, mica and rock-salt substrates 8 .…”

Section: B Stabilization Of Fcc Tungstenmentioning

confidence: 99%

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Ab initio based empirical potential applied to tungsten at high pressure

et al. 2017

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Density-functional theory forces, stresses and energies comprise a database from which the optimal parameters of a spline-based empirical potential combining Stillinger-Weber and modified embeddedatom forms are determined. Accuracy of the potential is demonstrated by calculations of ideal shear, stacking fault, vacancy migration, elastic constants and phonons all between 0 and 100 GPa. Consistency with existing models and experiments is demonstrated by predictions of screw dislocation core structure and deformation twinning in a tungsten nanorod. Lastly, the potential is used to study the stabilization of fcc tungsten at high pressure.

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Section: B Stabilization Of Fcc Tungstenmentioning

confidence: 99%

“…Much interest has been focused on α-W (bcc) and β-W (A15) nanostructures including nanorods 1-3 , nanoparticles [4][5][6][7] , and thin films [8][9][10] . Due to the technological importance of tungsten, classical interatomic potentials of various forms have been developed to study this metal [11][12][13][14][15][16][17][18] .…”

Section: Introductionmentioning

confidence: 99%

Ab initio based empirical potential applied to tungsten at high pressure

et al. 2017

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“…Deploying T e -dependent force fields has been attempted for just four materials that we are aware of: Si [32][33][34], W [35,36], Au [37], and Mo [38]. However, each one of these studies has a significant flaw.…”

Section: Introductionmentioning

confidence: 99%

Simulating electronically driven structural changes in silicon with two-temperature molecular dynamics

Darkins

Murphy

et al. 2018

Phys. Rev. B

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Radiation can drive the electrons in a material out of thermal equilibrium with the nuclei, producing hot, transient electronic states that modify the interatomic potential energy surface. We present a rigorous formulation of two-temperature molecular dynamics that can accommodate these electronic effects in the form of electronic-temperature-dependent force fields. Such a force field is presented for silicon, which has been constructed to reproduce the ab initio-derived thermodynamics of the diamond phase for electronic temperatures up to 2.5 eV, as well as the structural dynamics observed experimentally under nonequilibrium conditions in the femtosecond regime. This includes nonthermal melting on a subpicosecond timescale to a liquidlike state for electronic temperatures above ∼1 eV. The methods presented in this paper lay a rigorous foundation for the large-scale atomistic modeling of electronically driven structural dynamics with potential applications spanning the entire domain of radiation damage.

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“…Our threshold for track creation is lower than experimental observations [54,55], but this may be explained by the fact that fast monatomic ions deposit energy more widely amongst the targets electrons, leading to less damage. We also note that we have not included the changes in the interatomic interactions due to electronic excitation [56,57,58], which may influence the results. The effects of these modified interactions will be investigated, using electronic temperature dependent potentials, in future work.…”

Section: Resultsmentioning

confidence: 99%

The influence of the electronic specific heat on swift heavy ion irradiation simulations of silicon

Khara

Murphy

Daraszewicz

et al. 2016

J. Phys.: Condens. Matter

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Abstract. Swift heavy ion (SHI) irradiation of materials is often modelled using the two-temperature model. While the model has been successful in describing SHI damage in metals, it fails to account for the presence of a bandgap in semiconductors and insulators. Here we explore the potential to overcome this limitation by explicitly incorporating the influence of the bandgap in the parameterisation of the electronic specific heat for Si. The specific heat as a function of electronic temperature is calculated using finite temperature density functional theory with three different exchange correlation functionals, each with a characteristic bandgap. These electronic temperature dependent specific heats are employed with two temperature molecular dynamics to model ion track creation in Si. The results obtained using a specific heat derived from density functional theory showed dramatically reduced defect creation compared to models that used the free electron gas specific heat. As a consequence, the track radii are smaller and in much better agreement with experimental observations. We also observe a correlation between the width of the band gap and the track radius, arising due to the variation in the temperature dependence of the electronic specific heat.

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Dynamical simulations of an electronically induced solid-solid phase transformation in tungsten

Cited by 47 publications

References 67 publications

Ab initio based empirical potential applied to tungsten at high pressure

Ab initio based empirical potential applied to tungsten at high pressure

Simulating electronically driven structural changes in silicon with two-temperature molecular dynamics

The influence of the electronic specific heat on swift heavy ion irradiation simulations of silicon

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