Modellierung von bestrahlungsinduzierten Struktur- und Phasenübergängen in Nanomaterialien
Optik, Quantenoptik und Physik der Atome, Moleküle und Plasmen
Physikalische Chemie von Festkörpern und Oberflächen, Materialcharakterisierung
Zusammenfassung der Projektergebnisse
The main objective of the project was to explore fundamental physicochemical phenomena that govern structural and phase transitions in complex molecular systems coupled to radiation. Irradiation-driven chemical transformations form a basis for modern nanotechnologies, such as Focused Electron-Beam Induced Deposition (FEBID), which enables the controlled fabrication of nanostructures with nanometer resolution. However, despite the significant experimental progress in this area, there is still a lack of fundamental knowledge of the properties of irradiated nanosystems. A deeper understanding of the underlying physicochemical phenomena can facilitate a better control of electronic, mechanical and catalytic properties of such systems on the nanoscale. The project goals have been fulfilled by means of the advanced computational modeling approach combining classical molecular dynamics (MD), including MD with reactive force fields and Irradiation Driven Molecular Dynamics (IDMD) - the advanced computational methodology for the molecular-level description of chemical and irradiation-driven transformations. The combination of these computational approaches has opened new paths for unraveling properties of complex molecular systems coupled to radiation on the atomistic level. The work carried out in the project deepened the understanding of irradiation-induced nanoscale dynamics and chemistry involving metal and metal-containing nanostructures. Physical mechanisms of structural transformations in nanometer-sized metal clusters deposited on solid surfaces and structural transformations in deposited metal clusters exposed to an electron beam of a scanning transmission electron microscope were analyzed theoretically and computationally. Recent experiments with size-selected Au923 clusters softly deposited on a carbon substrate showed that the clusters undergo structural transformations from icosahedron (Ih) to decahedron (Dh) and face-center cubic structures upon the exposure to a 200-keV electron beam. It has been demonstrated theoretically that the energy relaxation in the deposited metal clusters through plasmon excitations formed in the clusters due to the interaction with low-energy secondary electrons emitted from the substrate can lead to the experimentally observed structural transformations. MD simulations of icosahedral Au923 clusters deposited on a carbon surface suggested a structural transformation from Ih to Dh structures, in agreement with experimental observations. The FEBID process for different experimentally relevant precursor molecules (W(CO)6, Fe(CO)5, Pt(PF3)4, Me2Au(tfac) and MeCpPtMe3) has been simulated at the atomistic level by means of the IDMD methodology. The IDMD methodology has enabled the first atomistic-level characterization of metal-containing nanostructures grown by the FEBID process. Understanding the structure and morphology of FEBID deposits at the atomistic level is important as the morphology of deposits governs many physical properties such as electrical and thermal conductivity and magnetic properties. The IDMD-based protocol for the atomistic simulation of FEBID enables the interpretation of many different experimental results and their predictability. Apart from that, it can be utilized to suggest the optimal parameters of the FEBID process (e.g. beam energy, current, beam size) for the growth of metal-containing structures with specific and/or tailored properties (e.g. nanogranular or metallic structures). The advanced computational approach exploited and validated in this project is not limited to the particular technological area of FEBID, but can be applied to other challenges, e.g. the investigation of irradiation-driven processes in space, effects of radiation in biological systems, or radiation induced nanocatalysis.
Projektbezogene Publikationen (Auswahl)
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Reactive molecular dynamics simulations of organometallic compound W(CO)6 fragmentation,. The European Physical Journal D, 73(10).
de Vera, Pablo; Verkhovtsev, Alexey; Sushko, Gennady & Solov’yov, Andrey V.
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Generalized correction to embedded-atom potentials for simulation of equilibrium and nonequilbrium properties of metals, St. Petersburg Polytechnical State University Journal. Physics and Mathematics 13(3) (2020) 23-41
A.V. Verkhovtsev, A.V. Korol, G.B. Sushko, S. Schramm & A.V. Solov’yov
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Multiscale simulation of the focused electron beam induced deposition process. Scientific Reports, 10(1).
de Vera, Pablo; Azzolini, Martina; Sushko, Gennady; Abril, Isabel; Garcia-Molina, Rafael; Dapor, Maurizio; Solov’yov, Ilia A. & Solov’yov, Andrey V.
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Soft landing of metal clusters on graphite: a molecular dynamics study. The European Physical Journal D, 74(10).
Verkhovtsev, Alexey V.; Erofeev, Yury & Solov’yov, Andrey V.
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Irradiation-driven molecular dynamics simulation of the FEBID process for Pt(PF3)4. Beilstein Journal of Nanotechnology, 12, 1151-1172.
Prosvetov, Alexey; Verkhovtsev, Alexey V.; Sushko, Gennady & Solov’yov, Andrey V.
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Irradiation-driven molecular dynamics: a review. The European Physical Journal D, 75(7).
Verkhovtsev, Alexey V.; Solov’yov, Ilia A. & Solov’yov, Andrey V.
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Atomistic simulation of the FEBID-driven growth of iron-based nanostructures. Physical Chemistry Chemical Physics, 24(18), 10807-10819.
Prosvetov, Alexey; Verkhovtsev, Alexey V.; Sushko, Gennady & Solov'yov, Andrey V.
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Dynamics of Systems on the Nanoscale, Springer Nature Switzerland, Cham (2022), 546 p.
I.A. Solov’yov, A.V. Verkhovtsev, A.V. Korol & A.V. Solov’yov
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Atomistic modeling of thermal effects in focused electron beam-induced deposition of Me2Au(tfac). The European Physical Journal D, 77(1).
Prosvetov, Alexey; Verkhovtsev, Alexey V.; Sushko, Gennady & Solov’yov, Andrey V.
