Rafał Topolnicki

Dr. Rafał Topolnicki

orcid

Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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23 November 2022 in Physical Review B
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Journal Article
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PSPiotr Sobota
Piotr Sobota
RTRafał Topolnicki
Rafał Topolnicki
TOTomasz Ossowski
Tomasz Ossowski
Tomasz PikulaTomasz Pikula
Tomasz Pikula
APAdam Pikul
Adam Pikul
RIRafał Idczak
Rafał Idczak
Structural and physical properties of the high-entropy alloy (NbTa)0.67(MoHfW)0.33 were studied by x-ray powder diffraction, energy dispersive x-ray spectroscopy, magnetization, electrical resistivity, and specific heat measurements. The experimental results were supported by theoretical calculations using two complementary approaches for electronic structure calculations: the Korringa-Kohn-Rostoker method with the coherent potential approximation (KKR-CPA) and projector augmented wave (PAW) within the density functional theory. It was found that the alloy forms with a cubic, body-centered structure (space group Im3¯m, W-type structure) with a lattice parameter a=3.287(1) Å and a random (but microscopically homogeneous) distribution of the constituent elements. At high temperature the alloy exhibits simple metallic behavior, while at low temperature it becomes a type-II superconductor with the critical temperature Tc≈4.3 K and the upper critical field μ0Hc2≈1.45 T. The electron-phonon coupling constant calculated from the PAW data, λel−phth−PAW=0.63, is in perfect agreement with the experimental results.

23 December 2024 in Acta Materialia
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Journal Article
Open access
PSPiotr Sobota
Piotr Sobota
BRBartosz Rusin
Bartosz Rusin
DGDaniel Gnida
Daniel Gnida
RTRafał Topolnicki
Rafał Topolnicki
TOTomasz Ossowski
Tomasz Ossowski
RIRafał Idczak
Rafał Idczak

1 September 2021 in The Journal of Physical Chemistry C
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Journal Article
Open access
RTRafał Topolnicki
Rafał Topolnicki
RKRobert Kucharczyk
Robert Kucharczyk
WKWojciech Kamiński
Wojciech Kamiński
We propose an efficient method to analyze the influence of thermal fluctuations of a molecular junction on its electronic transport properties, and consequently, reliably predict the time-averaged value of the conductance at a finite temperature in the zero-bias regime. Our multiscale approach combines three complementary techniques, namely, large-scale quantum mechanics/molecular mechanics (QM/MM) molecular dynamics (MD) simulations, active machine learning methods, and nonequilibrium Green’s function transport calculations. Results for the exemplary Au(111)-S-C6H4-C6H4-S-Au(111) and Au(111)-N-C6H4-C6H4-N-Au(111) junctions indicate the substantial impact of the thermal evolution of the junction on its transport properties, which cannot be forecasted based just on the ground-state geometry. In the experimentally relevant temperature range around the room temperature, the predicted conductance values are 30–40% larger than those calculated for the minimum-energy configuration of the respective junction at 0 K.

24 August 2023 in Materials
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RIRafał Idczak
Rafał Idczak
WNWojciech Michał Nowak
Wojciech Michał Nowak
BRBartosz Rusin
Bartosz Rusin
RTRafał Topolnicki
Rafał Topolnicki
TOTomasz Ossowski
Tomasz Ossowski
APAdam Pikul
Adam Pikul
The structural and physical properties of the new titanium- and niobium-rich type-A high-entropy alloy (HEA) superconductor Nb0.34Ti0.33Zr0.14Ta0.11Hf0.08 (in at.%) were studied by X-ray powder diffraction, energy dispersive X-ray spectroscopy, magnetization, electrical resistivity, and specific heat measurements. In addition, electronic structure calculations were performed using two complementary methods: the Korringa–Kohn–Rostoker Coherent Potential Approximation (KKR-CPA) and the Projector Augmented Wave (PAW) within Density Functional Theory (DFT). The results obtained indicate that the alloy exhibits type II superconductivity with a critical temperature close to 7.5 K, an intermediate electron–phonon coupling, and an upper critical field of 12.2(1) T. This finding indicates that Nb0.34Ti0.33Zr0.14Ta0.11Hf0.08 has one of the highest upper critical fields among all known HEA superconductors.

1 June 2014 in Applied Surface Science
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Journal Article
Closed access
RTRafał Topolnicki
Rafał Topolnicki
RKR. Kucharczyk
R. Kucharczyk

18 May 2025 in npj Computational Materials
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JNJan Navrátil
Jan Navrátil
RTRafał Topolnicki
Rafał Topolnicki
MOMichal Otyepka
Michal Otyepka
PBPiotr Błoński
Piotr Błoński
The rising demand for digital storage and environmental concerns necessitate ultra-high-density, energy-efficient solutions. Atomic-scale magnets (ASMs) based on transition metal (TM) dimers on defective graphene exhibit promising magnetic anisotropy energy (MAE) values, providing a robust barrier against magnetization reversal. However, identifying optimal TM-substrate configurations is challenging when relying solely on density functional theory (DFT) calculations with spin-orbit coupling. To address this, we developed a machine learning (ML) model trained on scalar-relativistic DFT data using a tree-based gradient boosting approach. Our model implicitly captures key physical interactions from second-order perturbation theory, ensuring reliable MAE predictions for systems beyond the training set. By bridging computational efficiency with interpretability, this work contributes to the development of ASMs for spintronics and quantum materials, offering a pathway to next-generation data storage technologies.