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Kinetic coefficients of metals ablated under the action of femtosecond laser pulses.

Kinetic coefficients of metals ablated under the action of femtosecond laser pulses. Yu.V. Petrov*, N.A. Inogamov*, K.P. Migdal**. * Landau Institute for Theoretical Physics, Chernogolovka ** All-Russia Research Institute of Automatics (VNIIA).

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Kinetic coefficients of metals ablated under the action of femtosecond laser pulses.

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  1. Kinetic coefficients of metals ablated under the action of femtosecond laser pulses. Yu.V. Petrov*, N.A. Inogamov*, K.P. Migdal** * Landau Institute for Theoretical Physics, Chernogolovka ** All-Russia Research Institute of Automatics (VNIIA)

  2. DoS for nickel and its parabolic approximation Also one constructed DoS for Al, Au, Cu, Fe, Pt, Ta using ABINIT* and Dmol³** *X. Gonze, B. Amadon, P.-M. Anglade et al., Computer Physics Communications, 2009.**http:\\www.accelrys.com\

  3. 2-parabolic DoS • Based on simple dispersion laws • 4 independent parameters for one metal • Gives the electronic thermodynamic properties such as a t. Explicit separation of the s- and d-branches of 2p DoS allows to distinguish the contributions of 2 conduction bands. • The electronic properties evaluated from 2p DoS are in good agreement with the data of DFT calculations.

  4. f-zone for Ta Data of Firefly* calculation** are used for the value of gap between f- and s-band *Alex A.Granovsky, Firefly version 7.1.G, www http://classic.chem.msu.su/gran/firefly/index.html ** Andrei Mukhanov, private communication

  5. Calculation of heat conductivity • Solution of Boltzmann equation in time relaxation approximation leads to the expressions for frequency of collisions of electron with momentum . • Frequencies of s-s and s-d collisions are used for calculation partial thermal conductivities.

  6. Calculation of heat conductivity • Thermodynamic values – from 2p partial DoS (s-branch). • Frequency of electron-ion collision – from the experimental data* for electric resistivity (via Drude formula). • Electron-electron collision frequencies find out from the expression in time relaxation approximation. *G. Pottlacher, High Temperature Thermophysical Properties of 22 Pure Metals, Keiper (2010).

  7. Heat conductivity for 5 metals In 1T state and at room temperature heat conductivity is less than in order of magnitude ( )

  8. Comparison with existing fitting* *D.S.Ivanov, L.V.Zhigilei. Phys.Rev.B,064114(2003). **N.A. Inogamov, Yu.V. Petrov. JETP, 137(3), pp. 505-529 (in Russian)

  9. Calculation of electron-phonon coupling • Bose-Einstein distribution for phonons • The rate of energy exchange by Kaganov* et al formula • Only longitudinal phonons are considered • Phonon dispersion law in Debye approach • The contributions of s- and d-band electrons in alpha are derived * M.I Kaganov, I.M. Lifshitz, L.V. Tanatarov. JETP. 31(232), 1956

  10. Electron-phonon coupling of Al and Au for gold renormalized to experimental data at room T is in agreement with Lin*. *Zh. Lin, L.V. Zhigilei, V. Celli, Phys. Rev. B 77,075133 (2008).

  11. Electron-phonon coupling for Fe,Ni,Ta • Sufficient difference between alpha Fe(3d64s2) and Ni(3d84s2) • Data for Ni compared with Lin* *Zh. Lin, L.V. Zhigilei, V. Celli, Phys. Rev. B 77,075133 (2008).

  12. Conclusion • The scheme for calculation of the electronic thermodynamic and kinetic properties for metals in 2T state. • Electron heat conductivity and electron-phonon coupling are evaluated for 7 metals (Al, Au, Cu, Fe, Ni, Pt, Ta).

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