MagTop’s theoretical research explores how electron interactions influence topological materials, particularly in systems where symmetry, spin-orbit coupling, and orbital structure all play a role .
One of our models [1] shows how combining Rashba spin-orbit coupling, an ionic lattice potential, and Zeeman splitting can lead to a quantum anomalous Hall insulator, even when electron correlations are strong. These correlations bring about changes not easily seen in spectral gaps, revealing many-body effects that challenge the standard view of topological phase transitions.
Building on that, we examined how interactions acting in the orbital basis – not just within energy bands – can lead to a topological Mott insulator states [2]. This route could be more natural in materials with f– or d-electrons, and we show how phase transitions in such systems don’t rely on gap closings but instead appear through more subtle changes, like kinks in the spectral function.
We also investigated the role of interactions in edge-state stability, finding that even weak correlations can open charge gaps and weaken the edge states, typically viewed as protected, if interactions are long-ranged [3]. As the system becomes more correlated, these states blend into the bulk, offering a new perspective on bulk-boundary correspondence in interacting systems.
Finally, we proposed a model that extends the Kane-Mele framework by adding localized orbitals to one sublattice [4]. This breaks inversion symmetry and creates new venue for interplay between correlations and topology. In systems with time-reversal symmetry, we find that interactions can actually stabilize the topological phase. When a weak magnetic field is added, the system exhibits split band inversion points – a behavior relevant to ferrovalley materials. These compounds, which use valley polarization instead of spin, could be key to developing future technologies in information storage known as valleytronics.
Together, these works deepen our understanding of how interactions can reshape some well-established topological behaviors, pointing to new opportunities in materials science, technology, and beyond.
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Figure: (Left panel) Topological phase transition in a Mott insulator is signaled by kink instead of gap closing [2]. |
| Figure: (Right panel) Weakening of the edge states by long-ranged interactions [3]. |  |
[1] M. M. Wysokiński, W. Brzezicki, Quantum anomalous Hall insulator in ionic Rashba lattice of correlated electrons, Phys. Rev. B 108, 035121 (2023).
[2] K. Jabłonowski, J. Skolimowski, K. Byczuk, M. M. Wysokiński, Topological Mott insulator in odd-integer filled Anderson lattice model with Hatsugai-Kohmoto interactions, Phys. Rev. B 108, 195145 (2023).
[3] J. Skolimowski, W. Brzezicki, Fate of gapless edge states in two-dimensional topological insulators with Hatsugai-Kohmoto interaction, Phys. Rev. B 111, 125135 (2025).
[4] J. Skolimowski, W. Brzezicki, C. Autieri, Impact of correlations on topology in the Kane-Mele model decorated with impurities, Phys. Rev. B 109, 075147 (2024).
MagTop’s theoretical research has concerned with effects of correlations in specific transition metal oxides and explored how their internal electronic structure can lead to unexpected magnetic and topological features.
One study focused on altermagnetism [1] – a type of antiferromagnets with spin-splitting that occurs without spin-orbit coupling – in materials like CaRuO and YVO. We showed that this behavior which emerges from orbital-selective physics and magnetic order, can be strengthen by local electron interactions. Interestingly, the nature of the magnetic order influences the symmetry of the Brillouin zone, suggesting a rich landscape where magnetism and electronic correlations intersect.
In another project [2], we developed a design strategy to realize robust topological insulators in cubic half-Heusler oxides. These materials don’t have inversion symmetry, but by fine-tuning the atomic positions and valence configurations, we identified compounds – especially in the α-phase – that show strong band inversion, a key ingredient for topological behavior. Among them, RbAuO stood out with significant band inversion and tunable surface states under strain, making it a candidate for room-temperature applications in spintronics and nanoelectronics.
Our third contribution revisits the Zaanen-Sawatzky-Allen classification, which helps to better understand electron behavior in strongly correlated systems [3]. By applying this framework to CaRuO, we broadened its relevance beyond traditional transition metal compounds. Here, the active electrons near the Fermi level come from ruthenium’s d-shells, and we demonstrate how combining modern computational techniques with this refined theory opens new ways to predict and explain the complex behavior of correlated materials.
These studies show how revisiting known materials with unconventional approaches can uncover new physical mechanisms – offering insight into magnetism, topology, and electronic correlation that could inspire future applications.
[1] G. Cuono, R. M. Sattigeri, J. Skolimowski, C. Autieri, Orbital-selective altermagnetism and correlation-enhanced spin-splitting in strongly-correlated transition metal oxides, J. Magn. Magn. Mat. 586, 171163 (2023),
[2] R. Dhori, R. M. Sattigeri, P. K. Jha, Non-trivial topological phases in transition metal rich half-Heusler oxides, J. Phys.: Condens. Matter 36, 055702 (2024),
[3] A. Romano, G. Cuono, J. Skolimowski, C. Autieri, C. Noce, The compound Ca2RuO4 within the Zaanen-Sawatzky-Allen approach, Physica C: Superconductivity and its applications 634, 1354725 (2025).