Development of an electron-temperature-dependent interatomic potential for molecular dynamics simulation of tungsten under electronic excitation

Khakshouri, Sascha; Alfè, Dario; Duffy, Dorothy M.

doi:10.1103/physrevb.78.224304

Cited by 79 publications

(59 citation statements)

References 41 publications

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“…Free-energy/volume surfaces were generated by performing single point simulations for a series of volumes for electronic temperatures between 0 and 30,000 K in increments of 5000 K. Potentials for intermediate temperatures were created us-ing cubic splines and stored in tabular form and can be found in the Supplementary Material 50 . Figure 2(a) shows that as the electronic temperature rises, the free energy decreases due to the increased importance of the entropy, T e S, contribution, in good agreement with previous results 45,51 . Furthermore, as the electronic temperature increases, the minimum in the free energy is shifted to larger volumes, implying that electronic excitation will cause expansion, as observed in the DFT-MD simulation above.…”

Section: Development Of the Te-dependent Potentialsupporting

confidence: 79%

“…Similarly the calculation of the effective density is treated using the original potential. Khakshouri et al 45 then developed a T e -dependent embedding term, based on a rectangular density of states, however here we adopt a much simpler approach. The T e -dependent embedding term is derived by fitting to the free energy-volume surface, calculated from high temperature DFT, for bcc tungsten.…”

Section: Development Of the Te-dependent Potentialmentioning

confidence: 99%

“…The potential parameters were derived using force matching and polynomials of different orders are used to show the parametric dependence on T e . The potential for W was based on the Finnis-Sinclair potential with a modified T e -dependent embedding term that incorporates changes in the potential energy and entropy due to electronic excitation explicitly 45 . This approach was extended to other bcc metals by Mason 46 .…”

Section: Development Of the Te-dependent Potentialmentioning

confidence: 99%

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

et al. 2015

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The rearrangement of a material's electron density during laser irradiation leads to modified non-thermal forces on the atoms that may lead to coherent atomic motions and structural phase transformations on very short timescales. We present ab initio molecular dynamics simulations of a martensitic solid-solid phase transformation in tungsten under conditions of strong electronic excitation. The transformation is ultrafast, taking just over a picosecond, and follows the tetragonal Bain path. To examine whether a solid-solid bccfcc phase transformation could occur during laser irradiation, we use two-temperature molecular dynamics (2T-MD) simulations with a specially developed potential dependent on the electronic temperature. Our simulations show that the occurrence of the solid-solid phase transformation is in competition with ultrafast non-thermally assisted melting with the strength of the electron-phonon coupling determining the lifetime of the new solid phase. In tungsten the melting transition is predicted to occur too rapidly for the fcc phase to be detectable during laser irradiation.

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Section: Development Of the Te-dependent Potentialsupporting

confidence: 79%

Section: Development Of the Te-dependent Potentialmentioning

confidence: 99%

Section: Development Of the Te-dependent Potentialmentioning

confidence: 99%

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

et al. 2015

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“…Even for a 50 keV cascade, most of the transitions stimulated are small on the scale of the width of the Fermi-Dirac distribution and so the evolution of the excitation spectrum takes the form of a one-dimensional diffusion in energy space. This strong evidence for a well-defined electronic temperature justifies an assumption often used to simplify the development of excitation dependent potentials for use in MD simulations of hot materials [151]. It will also greatly simplify efforts to devise and implement an augmented MD scheme that correctly treats energy exchange between ions and electrons.…”

Section: Time-dependent Tight-binding (Tdtb)mentioning

confidence: 99%

The treatment of electronic excitations in atomistic models of radiation damage in metals

Race¹,

Mason²,

Finnis³

et al. 2010

Rep. Prog. Phys.

135

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Abstract. Atomistic simulations are a primary means of understanding the damage done to metallic materials by high energy particulate radiation. In many situations the electrons in a target material are known to exert a strong influence on the rate and type of damage. The dynamic exchange of energy between electrons and ions can act to damp the ionic motion, to inhibit the production of defects or to quench in damage, depending on the situation. Finding ways to incorporate these electronic effects into atomistic simulations of radiation damage is a topic of current major interest, driven by materials science challenges in diverse areas such as energy production and device manufacture.In this review, we discuss the range of approaches that have been used to tackle these challenges. We compare augmented classical models of various kinds and consider recent work applying semi-classical techniques to allow the explicit incorporation of quantum mechanical electrons within atomistic simulations of radiation damage. We also outline the body of theoretical work on stopping power and electron-phonon coupling used to inform efforts to incorporate electronic effects in atomistic simulations and to evaluate their performance.

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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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Development of an electron-temperature-dependent interatomic potential for molecular dynamics simulation of tungsten under electronic excitation

Cited by 79 publications

References 41 publications

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

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

The treatment of electronic excitations in atomistic models of radiation damage in metals

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

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