# Published Data

### These pages provide an access point to data contained in CCFE published journal papers. By selecting a paper, and then a specific figure or table, you can request the related underlying data if it is available for release.

### Publication Figures

Publication Date:

2015-07-02

First Author:

Thomas D Swinburne

Title:

The phonon drag force acting on a mobile crystal defect: full treatment of discreteness and non-linearity

Paper Identifier:

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Figure Reference | Title | Description | Number of Figure Data Items | Identifier | Download Figure Details | ||
---|---|---|---|---|---|---|---|

Figure 1 | A cartoon of phonon scattering by a dislocation. | A cartoon of phonon scattering by a dislocation. Higher order scattering processes contribute terms of higherorder in temperature to the effective drag parameter. | 0 | CF/15/202 | Download | ||

Fig 2 | An illustration of the defect translation vector | An illustration of the defect translation vector for a localized `hump' in a chain of `atoms'. The vector describes the individual atomic displacements that correspond to an infinitesimal defect migration at zero temperature | 0 | CF/15/203 | Download | ||

Figure 3 | Migration barrier $E_{ m mig}$ and temperature independent friction coefficient $gamma_0$ as a function of kink width | Migration barrier $E_{rm mig}$ and temperature independent friction coefficient $gamma_0$ as a function of kink width $w$, relative to their values at $w=a$. We see the migration barrier decays exponentially, whilst the temperature independent friction coefficient remains almost unchanged even for kink widths much larger than the lattice parameter $a$. This highlights the fact that $gamma_0$ is a quantity owing its existence to the discreteness of the system, which is present even when the energy cost of discreteness is low. | 0 | CF/15/204 | Download | ||

Figure 4 | The diffusivity of an interstitial crowdion defect in W at various temperatures. | The diffusivity of an interstitial crowdion defect in W at various temperatures. | 0 | CF/15/205 | Download | ||

Figure 5 | Determination of ${f U}( m r)$ from MD simulation of a $1/2langle111 angle$ crowdion in W at T=300K. | Determination of ${bf U}(rm r)$ from MD simulation of a $1/2langle111rangle$ crowdion in W at T=300K. Below: The deviation in $1/2[111]$ bond length for ${bf U}(rm r)$ and ${bf X}(t)$. Inset: illustration of a $1/2langle111rangle$ crowdion fromcite{Dudarev2008}. Above: The thermal vibration vector ${bmPhi}={bf X}(t)-{bf U}({rm r})$, which fluctuates around zero with no peaks, as expected. Inset: Logarithmic plot of the quadratic weight $|({bf X}-{bf U}(rm r))cdotpartial_{rm r}{bf U}|^2$ for various values of $rm r$. We see a quadratic minimum of $sim10^{-7}$ which may be readily detected. | 0 | CF/15/206 | Download | ||

Figure 6 | The defect position, velocity and force acting on the defect, extracted for an interstitial crowdion in W at T=300K. | The defect position, velocity and force acting on the defect, extracted for an interstitial crowdion in W at T=300K. To our knowledge this is the first time a defect velocity and force have been extracted directly from the velocity and force vectors of a simulated crystal | 0 | CF/15/207 | Download | ||

Figure 7 | The defect force autocorrelation calculated from molecular dynamics simulations at various temperatures. | The defect force autocorrelation calculated from molecular dynamics simulations at various temperatures. The small supercell used for one of the T=150K autocorrelations contained $sim3,000$ atoms, whilst the other data was taken from supercells containing $sim10,000$ atoms. We see the initial peak of the force autocorrelation divided by $rm k_BT$ is essentially independent of temperature, giving an estimate for a temperature independent drag parameter $gamma=gamma_0simeq5.9$eV$cdot$ fs/${rmAA}^2$ that compares well with the value of $gamma_0$=6.0(7) eV$cdot$ fs/${rmAA}^2$ obtained from measurement of the diffusion constant $D={rm k_BT}/gamma_0$ | 0 | CF/15/208 | Download | ||

Figure 8 | The defect force autocorrelation calculated from molecular statics simulations for a crowdion in W | The defect force autocorrelation calculated from molecular statics simulations for a crowdion in W. We see that the autocorrelation is in good agreement with molecular dynamics estimates of the force autocorrelation. | 0 | CF/15/209 | Download | ||

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