Menno Bokdam
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Menno Bokdam has a total of 84 co-authors. Here are the top co-authors by number of shared publications:
Jonathan Lahnsteiner
VASP Software GmbH, Sensengasse 8/12, A-1090 Vienna, Austria
12 shared publicationsGeert Brocks
Faculty of Science and Technology and MESA+ Institute for Nanotechnology University of Twente P.O. Box 217 7500 AE Enschede The Netherlands
9 shared publications- Georg Kresse
Universität Wien
7 shared publications - Paul J. Kelly
University of Twente
7 shared publications - Cesare Franchini
University of Vienna
5 shared publications Georg Kresse
University of Vienna, Faculty of Physics and Center for Computational Materials Sciences, Sensengasse 8/12, 1090 Vienna, Austria
4 shared publications
Latest Publications
- Open Access
- 25 September 2026
- Published by Elsevier in SSRN Electronic Journal
Improved Coverage of Ultrathin Discontinuous Ru Films on Free-Standing Silicon Nitride via Plasma-Induced Surface Diffusion
The ongoing miniaturization of electronic devices depends on advances in thin-film technologies. In EUV lithography, ultrathin films are essential for pellicles, which protect photomasks from particle contamination. To combine high EUV transmission with mechanical and thermal stability, pellicles require free-standing layers with few-nanometers thick functional coatings. However, achieving continuous sub-5 nm films remains challenging, as reduced thickness delays film coalescence. At these thicknesses, the films are thermodynamically metastable and highly sensitive to external stimuli such as plasma, which can induce restructuring. Their atomic-scale response to plasma exposure is, however, not well understood. Here, we investigate the interaction of nitrogen plasma with ultrathin ruthenium films deposited on free-standing silicon nitride windows.Transmission electron microscopy of sub-5 nm Ru films reveals a strong thickness-dependent morphology change. As-deposited films show discontinuities, revealed as gaps between islands which diminish for increasing film thickness. Surprisingly, initial plasma exposure promotes gap closure, followed by solid-state dewetting at higher ion fluence. Supported by simulations, we show that surface diffusion and local atomic coordination affect the morphological evolution and can, under specific fluence conditions, improve coverage of initially discontinuous films. These findings provide new insights into plasma-assisted control of ultrathin film coverage for advanced EUV or microelectronic applications.
- 25 September 2026
- Published by Elsevier in SSRN Electronic Journal
Open AccessImproved Coverage of Ultrathin Discontinuous Ru Films on Free-Standing Silicon Nitride via Plasma-Induced Surface Diffusion
The ongoing miniaturization of electronic devices depends on advances in thin-film technologies. In EUV lithography, ultrathin films are essential for pellicles, which protect photomasks from particle contamination. To combine high EUV transmission with mechanical and thermal stability, pellicles require free-standing layers with few-nanometers thick functional coatings. However, achieving continuous sub-5 nm films remains challenging, as reduced thickness delays film coalescence. At these thicknesses, the films are thermodynamically metastable and highly sensitive to external stimuli such as plasma, which can induce restructuring. Their atomic-scale response to plasma exposure is, however, not well understood. Here, we investigate the interaction of nitrogen plasma with ultrathin ruthenium films deposited on free-standing silicon nitride windows.Transmission electron microscopy of sub-5 nm Ru films reveals a strong thickness-dependent morphology change. As-deposited films show discontinuities, revealed as gaps between islands which diminish for increasing film thickness. Surprisingly, initial plasma exposure promotes gap closure, followed by solid-state dewetting at higher ion fluence. Supported by simulations, we show that surface diffusion and local atomic coordination affect the morphological evolution and can, under specific fluence conditions, improve coverage of initially discontinuous films. These findings provide new insights into plasma-assisted control of ultrathin film coverage for advanced EUV or microelectronic applications.
- 8 April 2026
- Published by American Physical Society (APS) in Physical Review B
- Vol. 113 (14)
Smooth overlap of spin orientations: Machine learning exchange fields for ab initio spin dynamics
- 8 April 2026
- Published by American Physical Society (APS) in Physical Review B
- Vol. 113 (14)
Smooth overlap of spin orientations: Machine learning exchange fields for ab initio spin dynamics
- 16 March 2026
- Published by American Physical Society (APS) in Physical Review Materials
- Vol. 10 (3) , 036002
Simulating the influence of stoichiometry on the spectral emissivity of Mo x Si y thin films
In this work, we simulate the spectral emissivity of various stoichiometric crystal phases of ${\mathrm{Mo}}_{x}{\mathrm{Si}}_{y}$ compounds using density functional perturbation theory. The dielectric function, including electronic and ionic contributions, is calculated for each phase. We use the bulk properties obtained to simulate the optical absorption spectrum originating from the compound in thin film ($\ensuremath{\sim}20\phantom{\rule{0.28em}{0ex}}\mathrm{nm}$) form. We find that most thin films of ${\mathrm{Mo}}_{x}{\mathrm{Si}}_{y}$ are metallic, however, our results indicate that their emissivity is not simply correlated with the Mo content. For hot metallic films at around 900 K, we predict a maximal emissivity between 5--10 nm thickness. Our results are in good qualitative agreement with experiments, confirming that the emissivity of hexagonal ${\mathrm{MoSi}}_{2}$ is much lower than in the tetragonal phase. This is related to the small band gap (hexagonal ${\mathrm{MoSi}}_{2}$) and low density of states at the Fermi level (tetragonal ${\mathrm{MoSi}}_{2}$). Furthermore, test calculations on defected ${\mathrm{MoSi}}_{2}$ demonstrate that the infrared emissivity of ${\mathrm{MoSi}}_{2}$ thin films can be substantially increased by introducing defects.- 16 March 2026
- Published by American Physical Society (APS) in Physical Review Materials
- Vol. 10 (3) , 036002
Simulating the influence of stoichiometry on the spectral emissivity of Mo x Si y thin films
In this work, we simulate the spectral emissivity of various stoichiometric crystal phases of ${\mathrm{Mo}}_{x}{\mathrm{Si}}_{y}$ compounds using density functional perturbation theory. The dielectric function, including electronic and ionic contributions, is calculated for each phase. We use the bulk properties obtained to simulate the optical absorption spectrum originating from the compound in thin film ($\ensuremath{\sim}20\phantom{\rule{0.28em}{0ex}}\mathrm{nm}$) form. We find that most thin films of ${\mathrm{Mo}}_{x}{\mathrm{Si}}_{y}$ are metallic, however, our results indicate that their emissivity is not simply correlated with the Mo content. For hot metallic films at around 900 K, we predict a maximal emissivity between 5--10 nm thickness. Our results are in good qualitative agreement with experiments, confirming that the emissivity of hexagonal ${\mathrm{MoSi}}_{2}$ is much lower than in the tetragonal phase. This is related to the small band gap (hexagonal ${\mathrm{MoSi}}_{2}$) and low density of states at the Fermi level (tetragonal ${\mathrm{MoSi}}_{2}$). Furthermore, test calculations on defected ${\mathrm{MoSi}}_{2}$ demonstrate that the infrared emissivity of ${\mathrm{MoSi}}_{2}$ thin films can be substantially increased by introducing defects.- 30 December 2024
- Published by American Physical Society (APS) in Physical Review Materials
- Vol. 8 (12)
Observing structural distortions in a bilayer heterostructure on various [111] oriented substrates- 30 December 2024
- Published by American Physical Society (APS) in Physical Review Materials
- Vol. 8 (12)
Observing structural distortions in a bilayer heterostructure on various [111] oriented substrates- Open Access
- 16 January 2024
- Published by American Chemical Society (ACS) in The Journal of Physical Chemistry C
- Vol. 128 (3) , 1341-1349
Tuning Einstein Oscillator Frequencies of Cation Rattlers: A Molecular Dynamics Study of the Lattice Thermal Conductivity of CsPbBr3
- 16 January 2024
- Published by American Chemical Society (ACS) in The Journal of Physical Chemistry C
- Vol. 128 (3) , 1341-1349
Open AccessTuning Einstein Oscillator Frequencies of Cation Rattlers: A Molecular Dynamics Study of the Lattice Thermal Conductivity of CsPbBr3
- Open Access
Tuning Einstein Oscillator Frequencies of Cation Rattlers: A Molecular Dynamics Study of the Lattice Thermal Conductivity of CsPbBr$_3$
The pure CsPbBr$_3$ perovskite is an archetypal example of a strongly anharmonic crystal that poses a major challenge for computational methods to describe its thermodynamic properties. Its lattice dynamics exhibits characteristics of a phonon liquid: mode coupling, low lifetimes and `rattlers'. To study the thermal conduction in this crystal, including the effect of dynamic disorder introduced by the Cs rattlers, we apply large-scale molecular dynamics (MD) simulations combined with machine-learning interatomic potentials. We simulate its ultra-low lattice thermal conductivity in the cubic phase and obtain phonon spectra by measuring velocity autocorrelation functions. The thermal conductivity at 500 K is computed to be $0.53\pm0.04\frac{\rm W}{\rm m K}$, which is similar to that of demineralized water under normal indoor conditions. MD based insight into the heat transport mechanism of halide perovskites is presented. In the analysis the Cs cations are interpreted as damped Einstein oscillators. The phonon bandstructure of a system with artificially raised Cs masses demonstrates an increased interference of the Cs rattling with the acoustic phonon modes. We show that the thermal conductivity of the CsPbBr$_3$ perovskite can still be slightly decreased by tuning the cation rattling frequency into the range of the low lying acoustic modeOpen AccessTuning Einstein Oscillator Frequencies of Cation Rattlers: A Molecular Dynamics Study of the Lattice Thermal Conductivity of CsPbBr$_3$
The pure CsPbBr$_3$ perovskite is an archetypal example of a strongly anharmonic crystal that poses a major challenge for computational methods to describe its thermodynamic properties. Its lattice dynamics exhibits characteristics of a phonon liquid: mode coupling, low lifetimes and `rattlers'. To study the thermal conduction in this crystal, including the effect of dynamic disorder introduced by the Cs rattlers, we apply large-scale molecular dynamics (MD) simulations combined with machine-learning interatomic potentials. We simulate its ultra-low lattice thermal conductivity in the cubic phase and obtain phonon spectra by measuring velocity autocorrelation functions. The thermal conductivity at 500 K is computed to be $0.53\pm0.04\frac{\rm W}{\rm m K}$, which is similar to that of demineralized water under normal indoor conditions. MD based insight into the heat transport mechanism of halide perovskites is presented. In the analysis the Cs cations are interpreted as damped Einstein oscillators. The phonon bandstructure of a system with artificially raised Cs masses demonstrates an increased interference of the Cs rattling with the acoustic phonon modes. We show that the thermal conductivity of the CsPbBr$_3$ perovskite can still be slightly decreased by tuning the cation rattling frequency into the range of the low lying acoustic mode - Open Access
Phase transitions of LaMnO$_3$ and SrRuO$_3$ from DFT + U based machine learning force fields simulations
Perovskite oxides are known to exhibit many magnetic, electronic and structural phases as function of doping and temperature. These materials are theoretically frequently investigated by the DFT+U method, typically in their ground state structure at $T=0$. We show that by combining machine learning force fields (MLFFs) and DFT+U based molecular dynamics, it becomes possible to investigate the crystal structure of complex oxides as function of temperature and $U$. Here, we apply this method to the magnetic transition metal compounds LaMnO$_3$ and SrRuO$_3$. We show that the structural phase transition from orthorhombic to cubic in LaMnO$_3$, which is accompanied by the suppression of a Jahn-Teller distortion, can be simulated with an appropriate choice of $U$. For SrRuO$_3$, we show that the sequence of orthorhombic to tetragonal to cubic crystal phase transitions can be described with great accuracy. We propose that the $U$ values that correctly capture the temperature-dependent structures of these complex oxides, can be identified by comparison of the MLFF simulated and experimentally determined structures.Open AccessPhase transitions of LaMnO$_3$ and SrRuO$_3$ from DFT + U based machine learning force fields simulations
Perovskite oxides are known to exhibit many magnetic, electronic and structural phases as function of doping and temperature. These materials are theoretically frequently investigated by the DFT+U method, typically in their ground state structure at $T=0$. We show that by combining machine learning force fields (MLFFs) and DFT+U based molecular dynamics, it becomes possible to investigate the crystal structure of complex oxides as function of temperature and $U$. Here, we apply this method to the magnetic transition metal compounds LaMnO$_3$ and SrRuO$_3$. We show that the structural phase transition from orthorhombic to cubic in LaMnO$_3$, which is accompanied by the suppression of a Jahn-Teller distortion, can be simulated with an appropriate choice of $U$. For SrRuO$_3$, we show that the sequence of orthorhombic to tetragonal to cubic crystal phase transitions can be described with great accuracy. We propose that the $U$ values that correctly capture the temperature-dependent structures of these complex oxides, can be identified by comparison of the MLFF simulated and experimentally determined structures. - 5 December 2023
- Published by American Physical Society (APS) in Physical Review B
- Vol. 108 (23) , 235122
Phase transitions of and from based machine learning force fields simulationsPerovskite oxides are known to exhibit many magnetic, electronic, and structural phases as function of doping and temperature. These materials are theoretically frequently investigated by the method, typically in their ground state structure at . We show that by combining machine learning force fields (MLFFs) and based molecular dynamics, it becomes possible to investigate the crystal structure of complex oxides as function of temperature and . Here, we apply this method to the magnetic transition metal compounds and . We show that the structural phase transition from orthorhombic to cubic in , which is accompanied by the suppression of a Jahn-Teller distortion, can be simulated with an appropriate choice of . For , we show that the sequence of orthorhombic to tetragonal to cubic crystal phase transitions can be described with great accuracy. We propose that the values that correctly capture the temperature-dependent structures of these complex oxides can be identified by comparison of the MLFF simulated and experimentally determined structures.- 5 December 2023
- Published by American Physical Society (APS) in Physical Review B
- Vol. 108 (23) , 235122
Phase transitions of and from based machine learning force fields simulationsPerovskite oxides are known to exhibit many magnetic, electronic, and structural phases as function of doping and temperature. These materials are theoretically frequently investigated by the method, typically in their ground state structure at . We show that by combining machine learning force fields (MLFFs) and based molecular dynamics, it becomes possible to investigate the crystal structure of complex oxides as function of temperature and . Here, we apply this method to the magnetic transition metal compounds and . We show that the structural phase transition from orthorhombic to cubic in , which is accompanied by the suppression of a Jahn-Teller distortion, can be simulated with an appropriate choice of . For , we show that the sequence of orthorhombic to tetragonal to cubic crystal phase transitions can be described with great accuracy. We propose that the values that correctly capture the temperature-dependent structures of these complex oxides can be identified by comparison of the MLFF simulated and experimentally determined structures.- Open Access
- 5 May 2023
- Published by American Chemical Society (ACS) in The Journal of Physical Chemistry C
- Vol. 127 (19) , 9183-9195
Dynamic Distortions of Quasi-2D Ruddlesden–Popper Perovskites at Elevated Temperatures: Influence on Thermal and Electronic Properties
- 5 May 2023
- Published by American Chemical Society (ACS) in The Journal of Physical Chemistry C
- Vol. 127 (19) , 9183-9195
Open AccessDynamic Distortions of Quasi-2D Ruddlesden–Popper Perovskites at Elevated Temperatures: Influence on Thermal and Electronic Properties
- Open Access
- 1 February 2023
- Published by Royal Society of Chemistry (RSC) in Journal of Materials Chemistry A
- Vol. 11 (9) , 4587-4597
Disorder to order: how halide mixing in MAPbI 3− x Br x perovskites restricts MA dynamics
This work reveals the correlation between anisotropy in MA + reorientation dynamics and the nearest-neighbour halide layout, which is associated with the composition in mixed lead halide MAPbI 3− x Br x perovskites.
- 1 February 2023
- Published by Royal Society of Chemistry (RSC) in Journal of Materials Chemistry A
- Vol. 11 (9) , 4587-4597
Open AccessDisorder to order: how halide mixing in MAPbI 3− x Br x perovskites restricts MA dynamics
This work reveals the correlation between anisotropy in MA + reorientation dynamics and the nearest-neighbour halide layout, which is associated with the composition in mixed lead halide MAPbI 3− x Br x perovskites.