Fields of Research and Scientific Interests

1. The Influence of Disorder and Impurities on the Superconducting Properties of Materials

The relationship between disorder and superconductivity is a very interesting and intriguing phenomenon in condensed matter physics. It is well known that conventional superconductors with a homogeneous order parameter are insensitive to a small concentration of non-magnetic impurities. This property is known as Anderson's theorem. In the strong disorder regime, superconductivity is destroyed and even a superconductor-to-insulator transition occurs. Between these limiting cases, the most interesting regime can arise where disorder even enhances superconductivity, as observed in some alloys or granular materials. The mechanisms of this enhancement are not entirely clear to date and are actively being researched.

2. Magnetism and Superconductivity
Recent advances in the study of ferromagnetic superconductors have revealed many new and interesting aspects of the physics of superconductivity, particularly concerning the magnetic properties of superconductors. The coexistence of superconductivity and magnetism in such materials critically depends on how the magnetic and superconducting subsystems are coupled. Namely, the most important factor is which of the two subsystems is "the strongest", i.e., which of the two critical temperatures is the highest—the Curie temperature of magnetic ordering Tm or the critical temperature of superconductivity Tc. Recent experimental results have drawn attention to the study of ferromagnetic superconductors in which the superconducting subsystem is "stronger". In this case, not just ordinary ferromagnetic domains with corrections due to superconductivity appear, but self-organized structures are observed that do not exist in either ferromagnetic or superconducting materials. The classification and description of such structures are currently lacking and require detailed theoretical and experimental studies.

3. Low-Dimensional Superconducting Metamaterials
The interaction and clustering of magnetic vortices in thin superconducting films represent a fundamental example of self-organization in condensed matter physics. Thin films made from a type-I material often behave like type-II superconductors due to the influence of stray magnetic fields. However, there is a broad intermediate parameter region—the intertype regime—where superconductivity does not belong to either classical type. It is in this regime that the competition between long-range repulsion and short-range attraction between vortices gives rise to exotic states of vortex matter, such as stable chains and clusters. This phenomenon demonstrates how low-dimensional geometry enables the creation of superconducting metamaterials with controllable collective states, promising for fundamental research and applications in electronics.

4. Properties of Intertype Superconductors
Intertype superconductors, located in the transitional regime between types I and II, are characterized by the formation of an intermediate mixed state. In this state, vortex-free domains coexist with exotic magnetic flux configurations—vortex lattices, vortex chains, and clusters. A key feature is the interaction between vortices, which under certain conditions becomes attractive, leading to their spontaneous self-organization into ordered superstructures. This universal pattern formation mechanism, driven by proximity to the Bogomol'nyi point, is confirmed by agreement between modern experiments and theoretical calculations.

5. Superconductors with a Multicomponent Condensate
Superconductors with a multicomponent condensate are systems where the superconducting state is formed jointly by electrons from several different energy bands. The key feature of such materials is not merely the presence of multiple gaps in the excitation spectrum, but the coexistence of several condensates with different characteristics, such as characteristic coherence length and binding energy. Contrary to simplified views, even with degenerate gaps, multiband nature radically affects the properties: interference between condensates can significantly alter magnetic properties, leading to the emergence of an intertype regime between type-I and type-II superconductivity. Moreover, interband interaction of condensates can suppress destructive fluctuations in low-dimensional subsystems, leading to a sharp increase in critical temperature and enhanced coherence, especially near Lifshitz transitions. Thus, controlling the interaction between condensate components opens pathways to creating high-temperature superconductors with unique and robust properties.

6. Two-Dimensional Semiconductor Structures
Two-dimensional semiconductor structures, such as transition metal dichalcogenide monolayers, are characterized by strong Coulomb interactions leading to the formation of stable excitonic complexes (trions, polarons). Their electronic structure and dynamics are effectively investigated using nonlinear optical methods, for example, second-harmonic generation, which is sensitive to the type of excitonic states and the dielectric environment. The interaction of charge carriers with phonons causes polaronic effects, including bandgap renormalization, which significantly influences the optical and transport properties of these materials.

7. Semiconductor Quantum Dots
Semiconductor quantum dots are nanocrystals exhibiting artificial atom-like properties due to quantum confinement of charge carriers, which gives them a discrete energy spectrum. These characteristics make them a promising platform for quantum technologies, particularly for creating single-photon sources and qubits. Active research focuses on controlling quantum dot states using laser radiation, generating entangled light states, and realizing non-classical photon states, such as Fock states. An important direction is also the development of quantum memory elements based on hybrid "quantum dot–optical resonator" systems. One of the most interesting challenges in this field is suppressing the destabilizing influence of the environment, for example, interaction with phonons, to preserve state coherence and improve device efficiency.