Effect of Intense Laser Irradiation on the Lattice Stability of Semiconductors and Metals

Recoules, V.; Clérouin, Jean; Zérah, G.; Anglade, Pierre-Matthieu; Mazevet, S.

doi:10.1103/physrevlett.96.055503

Cited by 275 publications

(309 citation statements)

References 26 publications

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“…This requires a number of parameters to be fitted. Another model ignores the dynamics that created the excited electronic states, replacing it by a thermal ensemble of electrons [22]. One can carry out the TDDFT calculation of the linear response of the thermal system and compare it directly with the response to the pumpexcited system.…”

Section: Introductionmentioning

confidence: 99%

Numerical pump-probe experiments of laser-excited silicon in nonequilibrium phase

et al. 2014

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We calculate the dielectric response of crystalline silicon following irradiation by a high-intensity laser pulse, modeling the dynamics by time-dependent density functional theory (TDDFT). The pump-probe measurements are numerically simulated by solving the time-dependent Kohn-Sham equation with the pump and probe fields included as external fields. As expected, the excited silicon shows features of a particle-hole plasma in its response. We compare the calculated response with a thermal model and with a simple Drude model. The thermal model requires only a static DFT calculation to prepare electronically excited matter and agrees rather well with the TDDFT for the same particle-hole density. The Drude model with two fitted parameters (electron effective mass and collision time) also shows fair agreement at the lower excitation energies; the fitted effective masses are consistent with carrier-band dispersions. The extracted Drude lifetimes range from 6 fs at weak pumping fields to much lower values at high fields. However, we find that the Drude model does not give a good fit to the imaginary dielectric function at the highest fields. Comparing the thermal model with the Drude, we find that the extracted lifetimes are in the same range, 1-13 fs depending on the temperature. These short Drude lifetimes show that strong damping is possible in the TDDFT, despite the absence of electron scattering. One significant difference between the TDDFT response and the other models is that the response to the probe pulse depends on the polarization of the pump pulse. We also find that the imaginary part of the dielectric function can be negative, particularly for the parallel polarization of pump and probe fields.

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Section: Introductionmentioning

confidence: 99%

Numerical pump-probe experiments of laser-excited silicon in nonequilibrium phase

et al. 2014

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“…[1][2][3] Laser-induced heating, 4 melting, 5 laser ablation, 6 shock wave dynamics, 7 Coulomb explosions, 8 and plasma formation 9 are typical examples. Lasermaterial interactions are heavily dependent on laser beam parameters such as pulse duration, intensity, and wavelength, as well as on material properties such as the band gap for semiconductors and dielectrics.…”

Section: Introductionmentioning

confidence: 99%

Multiphoton absorption in germanium using pulsed infrared free-electron laser radiation

et al. 2011

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We report wavelength-and intensity-dependent transmission measurements of intense mid-infrared radiation from the Vanderbilt Free Electron Laser in single-crystal Ge(100) in the wavelength range of 2.8-5.2 μm. This range accesses both the direct and indirect energy gaps in Ge, requiring in each case either two or three photons (2PA or 3PA) for absorption. Large changes in the multi-photon absorption rate are seen at the direct-to-indirect and 2PA-to-3PA transitions. Photon interactions are dominated by free carrier absorption (FCA), primarily due to holes. The entire absorption process is modeled with the two-and three-photon absorption coefficients (β and γ) as fitting parameters.Using newly measured values of the low-intensity FCA cross-sections, we find a best fit to the data at 2.8 µm that is in agreement with theory and previous measurements. We report a ratio of 175 for β across the direct-to-indirect transition, and a ratio of 5 across the same transition for γ. These ratios are independent of systematic variations in free carrier cross-sections and beam diameter. Receipt

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“…Contemporary computations on WDM [5][6][7][8][9][10][11][12][13][14][15][16][17][18] are dominated by use of the Kohn-Sham (KS) realization of thermal density functional theory (DFT) [19][20][21][22][23][24][25] to generate a potential surface for ionic motion (treated classically). The majority of such calculations use approximate ground-state exchange-correlation (XC) functionals, E xc , with the temperature dependence of the XC free energy picked up implicitly from the T-dependence of the density n(r, T).…”

Section: Introductionmentioning

confidence: 99%

Temperature-dependent behavior of confined many-electron systems in the Hartree-Fock approximation

2012

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Many-electron systems confined at substantial finite temperatures and densities present a major challenge to density functional theory. In particular, there is comparatively little systematic knowledge about the behavior of free-energy density functionals for temperatures and pressures of interest, for example, in the study of warm dense matter. As with ground-state functionals, development of approximate free-energy functionals is faced with significant needs for reliable assessment and calibration data. Here we address, in part, this need for detailed results on well-characterized systems. We present results on a comparatively simple, well-defined, computationally feasible but previously unexplored model, the thermal Hartree-Fock approximation. We discuss the main technical tasks (defining a suitable basis and evaluation of the required matrix elements) and give an illustrative initial application which probes both the content of the model and the solution techniques: a system of eight one-electron atoms with nuclei at fixed, arbitrary positions in a hard-walled box. Even this simple system produces physical behavior different from that produced by simple ground state density functionals used at finite temperature (a common approximation in the study of WDM).

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Effect of Intense Laser Irradiation on the Lattice Stability of Semiconductors and Metals

Cited by 275 publications

References 26 publications

Numerical pump-probe experiments of laser-excited silicon in nonequilibrium phase

Numerical pump-probe experiments of laser-excited silicon in nonequilibrium phase

Multiphoton absorption in germanium using pulsed infrared free-electron laser radiation

Temperature-dependent behavior of confined many-electron systems in the Hartree-Fock approximation

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