Nonequilibrium Green's functions and atom-surface dynamics: Simple views from a simple model system

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Nonequilibrium Green's functions and atom-surface dynamics: Simple views from a simple model system. / Vinas Boström, Emil; Hopjan, Miroslav; Kartsev, Alexey; Verdozzi, Claudio; Almbladh, Carl-Olof.

I: Journal of Physics: Conference Series, Vol. 696, Nr. 1, 012007, 12.04.2016.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

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TY - JOUR

T1 - Nonequilibrium Green's functions and atom-surface dynamics: Simple views from a simple model system

AU - Vinas Boström, Emil

AU - Hopjan, Miroslav

AU - Kartsev, Alexey

AU - Verdozzi, Claudio

AU - Almbladh, Carl-Olof

PY - 2016/4/12

Y1 - 2016/4/12

N2 - We employ Non-equilibrium Green's functions (NEGF) to describe the real-time dynamics of an adsorbate-surface model system exposed to ultrafast laser pulses. For a finite number of electronic orbitals, the system is solved exactly and within different levels of approximation. Specifically i) the full exact quantum mechanical solution for electron and nuclear degrees of freedom is used to benchmark ii) the Ehrenfest approximation (EA) for the nuclei, with the electron dynamics still treated exactly. Then, using the EA, electronic correlations are treated with NEGF within iii) 2nd Born and with iv) a recently introduced hybrid scheme, which mixes 2nd Born self-energies with non-perturbative, local exchange- correlation potentials of Density Functional Theory (DFT). Finally, the effect of a semi-infinite substrate is considered: we observe that a macroscopic number of de-excitation channels can hinder desorption. While very preliminary in character and based on a simple and rather specific model system, our results clearly illustrate the large potential of NEGF to investigate atomic desorption, and more generally, the non equilibrium dynamics of material surfaces subject to ultrafast laser fields.

AB - We employ Non-equilibrium Green's functions (NEGF) to describe the real-time dynamics of an adsorbate-surface model system exposed to ultrafast laser pulses. For a finite number of electronic orbitals, the system is solved exactly and within different levels of approximation. Specifically i) the full exact quantum mechanical solution for electron and nuclear degrees of freedom is used to benchmark ii) the Ehrenfest approximation (EA) for the nuclei, with the electron dynamics still treated exactly. Then, using the EA, electronic correlations are treated with NEGF within iii) 2nd Born and with iv) a recently introduced hybrid scheme, which mixes 2nd Born self-energies with non-perturbative, local exchange- correlation potentials of Density Functional Theory (DFT). Finally, the effect of a semi-infinite substrate is considered: we observe that a macroscopic number of de-excitation channels can hinder desorption. While very preliminary in character and based on a simple and rather specific model system, our results clearly illustrate the large potential of NEGF to investigate atomic desorption, and more generally, the non equilibrium dynamics of material surfaces subject to ultrafast laser fields.

U2 - 10.1088/1742-6596/696/1/012007

DO - 10.1088/1742-6596/696/1/012007

M3 - Article

VL - 696

JO - Journal of Physics: Conference Series

JF - Journal of Physics: Conference Series

SN - 1742-6596

IS - 1

M1 - 012007

ER -