Russian Scientists Demonstrate How Disorder Contributes to Emergence of Unusual Superconductivity
Researchers at HSE University and MIPT have investigated how the composition of electrons in a superconductor influences the emergence of intertype superconductivity—a unique state in which superconductors display unusual properties. It was previously believed that intertype superconductivity occurs only in materials with minimal impurities. However, the scientists discovered that the region of intertype superconductivity not only persists but can also expand in materials with a high concentration of impurities and defects. In the future, these superconductors could contribute to the development of highly sensitive sensors and detectors. The study has been published in Frontiers of Physics.
In ordinary materials, there is always at least some resistance, a property that hinders the flow of electric current and results in energy loss. However, certain materials, when cooled to extremely low temperatures, transition into a state where resistance is entirely eliminated. This state is known as superconductivity, and the materials exhibiting it are called superconductors.
When a material enters a superconducting state, it completely expels external magnetic fields, such as those generated by electromagnets or current-carrying conductors. However, if the external magnetic field becomes too strong, the superconductor loses its properties and reverts to its normal state.
Superconductors are traditionally classified into two types. Their classification into type I or type II depends on the material's behaviour in a magnetic field and the value of the Ginzburg–Landau parameter, which, in turn, depends on the material's characteristics as well as the presence of impurities and defects. If it is below a certain value, the material is classified as a type I superconductor; if it is above that value, it is classified as a type II superconductor. In type I superconductors, the magnetic field is expelled from the material until its intensity reaches a critical value. After that, the field penetrates the material, and superconductivity is lost. In type II superconductors, the situation is different: the magnetic field begins to penetrate once the field strength exceeds a minimum threshold, but superconductivity is maintained. The field penetrates in the form of vortices—narrow current-carrying tubes, within which a magnetic field is present. These vortices form an ordered lattice structure.
However, there is a narrow region around the critical value of the Ginzburg–Landau parameter where superconductivity exhibits intermediate properties between type I and type II. This state is known as intertype superconductivity. Unusual magnetic field configurations differing from lattices arise in this state, including vortex clusters, chains, and giant vortices, which give rise to new magnetic properties distinct from the classical ones.
Initially, intertype superconductivity was observed only in pure superconductors with minimal impurities. However, a recent study by scientists at the HSE MIEM Centre for Quantum Metamaterials and the MIPT Centre for Advanced Methods of Mesophysics and Nanotechnology revealed that the region of intertype superconductivity is maintained in superconductors with a high concentration of impurities and defects. This is possible in multiband superconductors, where multiple 'types' of electrons with different properties coexist. Electrons from different energy bands respond differently to impurities: some are more affected, while others are less so. Moreover, the extent of interaction with impurities can be controlled, for instance, by irradiating the material with ions, which allows for the expansion of the intertype superconductivity region.
The scientists' findings contribute to the current understanding of superconductivity types and how their properties change under different conditions. This is crucial for the effective use of superconductors in cables and high-power magnets, as the current and magnetic properties of a superconductor depend on its type. It is also valuable for the development of new, highly sensitive devices.
'The study broadens our understanding of superconductivity and the classical classification of superconductors, which has been around for about 70 years. We have shown that the combination of disorder and multiband effects fundamentally alters the properties of superconductors and opens up the possibility of exploring rare and exotic superconducting states. Since the magnetic field configurations in intertype superconductivity are sensitive to temperature and current parameters, such superconductors could be used in highly sensitive sensors and detectors in the future,' according to Pavel Marychev, Research Fellow at the HSE Centre for Quantum Metamaterials.
See also:
Habits Stem from Childhood: School Years Found to Shape Leisure Preferences in Adulthood
Moving to a big city does not necessarily lead to dramatic changes in daily habits. A study conducted at HSE University found that leisure preferences in adulthood are largely shaped during childhood and are influenced by where individuals spent their school years. This conclusion was drawn by Sergey Korotaev, Research Fellow at the HSE Faculty of Economic Sciences, from analysing the leisure habits of more than 5,000 Russians.
Russian Scientists Reconstruct Dynamics of Brain Neuron Model Using Neural Network
Researchers from HSE University in Nizhny Novgorod have shown that a neural network can reconstruct the dynamics of a brain neuron model using just a single set of measurements, such as recordings of its electrical activity. The developed neural network was trained to reconstruct the system's full dynamics and predict its behaviour under changing conditions. This method enables the investigation of complex biological processes, even when not all necessary measurements are available. The study has been published in Chaos, Solitons & Fractals.
Scientists Propose Novel Theory on Origin of Genetic Code
Alan Herbert, Scientific Supervisor of the HSE International Laboratory of Bioinformatics, has put forward a new explanation for one of biology's enduring mysteries—the origin of the genetic code. According to his publication in Biology Letters, the contemporary genetic code may have originated from self-organising molecular complexes known as ‘tinkers.’ The author presents this novel hypothesis based on an analysis of secondary DNA structures using the AlphaFold 3 neural network.
See, Feel, and Understand: HSE Researchers to Explore Mechanisms of Movement Perception in Autism
Scientists at the HSE Cognitive Health and Intelligence Centre have won a grant from the Russian Science Foundation (RSF) to investigate the mechanisms of visual motion perception in autism. The researchers will design an experimental paradigm to explore the relationship between visual attention and motor skills in individuals with autism spectrum disorders. This will provide insight into the neurocognitive mechanisms underlying social interaction difficulties in autism and help identify strategies for compensating for them.
Scholars Disprove Existence of ‘Crisis of Trust’ in Science
An international team of researchers, including specialists from HSE University, has conducted a large-scale survey in 68 countries on the subject of trust in science. In most countries, people continue to highly value the work of scientists and want to see them take a more active role in public life. The results have been published in Nature Human Behaviour.
Education System Reforms Led to Better University Performance, HSE Researchers Find
A study by researchers at the HSE Faculty of Economic Sciences and the Institute of Education have found that the number of academic papers published by research universities in international journals has tripled in the past eight years. Additionally, universities have developed more distinct specialisations. Thus, sectoral universities specialising in medical, pedagogical, technical, and other fields are twice as likely to admit students to target places. The study has been published in Vocation, Technology & Education.
Scientists Record GRB 221009A, the Brightest Gamma-Ray Burst in Cosmic History
A team of scientists from 17 countries, including physicists from HSE University, analysed early photometric and spectroscopic data of GRB 221009A, the brightest gamma-ray burst ever recorded. The data was obtained at the Sayan Observatory one hour and 15 minutes after the emission was registered. The researchers detected photons with an energy of 18 teraelectronvolts (TeV). Theoretically, such high-energy particles should not reach Earth, but data analysis has confirmed that they can. The results challenge the theory of gamma radiation absorption and may point to unknown physical processes. The study has been published in Astronomy & Astrophysics.
Chemists Simplify Synthesis of Drugs Involving Amide Groups
Chemists from HSE University and the Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences (INEOS RAS) have developed a new method for synthesising amides, essential compounds in drug production. Using a ruthenium catalyst and carbon monoxide under precisely controlled reaction conditions, they successfully obtained the target product without by-products or complex purification steps. The method has already been tested for synthesising a key component of Vorinostat, a drug used to treat T-cell lymphoma. This approach could lower the cost of the drug by orders of magnitude. The paper has been published in the Journal of Catalysis. The study was supported by the Russian Science Foundation.
Scientists Examine Neurobiology of Pragmatic Reasoning
An international team including scientists from HSE University has investigated the brain's ability to comprehend hidden meanings in spoken messages. Using fMRI, the researchers found that unambiguous meanings activate brain regions involved in decision-making, whereas processing complex and ambiguous utterances engages regions responsible for analysing context and the speaker's intentions. The more complex the task, the greater the interaction between these regions, enabling the brain to decipher the meaning. The study has been published in NeuroImage.
Scientists Present New Solution to Imbalanced Learning Problem
Specialists at the HSE Faculty of Computer Science and Sber AI Lab have developed a geometric oversampling technique known as Simplicial SMOTE. Tests on various datasets have shown that it significantly improves classification performance. This technique is particularly valuable in scenarios where rare cases are crucial, such as fraud detection or the diagnosis of rare diseases. The study's results are available on ArXiv.org, an open-access archive, and will be presented at the International Conference on Knowledge Discovery and Data Mining (KDD) in summer 2025 in Toronto, Canada.