Scientists discover how correlated disorder boosts superconductivity

(Press-News.org) Superconductivity is a unique state of matter in which electric current flows without any energy loss. In materials with defects, it typically emerges at very low temperatures and develops in several stages. An international team of scientists, including physicists from HSE MIEM, has demonstrated that when defects within a material are arranged in a specific pattern rather than randomly, superconductivity can occur at a higher temperature and extend throughout the entire material. This discovery could help develop superconductors that operate without the need for extreme cooling. The study has been published in Physical Review B.

Superconductivity is a state in which electric current flows through a material without any energy loss. In conventional conductors, part of the energy is converted into heat, but in superconductors, this does not occur—current flows freely and does not weaken. Today, superconductors are used in applications such as MRI machines, where superconducting coils generate strong magnetic fields. In the future, superconductors may also be integrated into systems that require lossless power transmission and high-speed signal processing. The challenge is that nearly all superconductors function only at temperatures below -140 °C, which limits their practical use. To make them more viable, physicists are working to raise their operating temperature and improve stability. 

Researchers from the HSE MIEM Centre for Quantum Metamaterials, in collaboration with colleagues from MEPhI, MIPT, and the Federal University of Pernambuco, Brazil, have shown that superconductivity can be made more stable by controlling the placement of defects. Defects are deviations from a material’s ideal crystal lattice, such as excess or missing atoms, impurities, and distortions. They usually disrupt the movement of electrons and weaken superconductivity, but it is impossible to eliminate them entirely, especially in multicomponent materials. Rather than eliminating these imperfections, the scientists have proposed arranging them in a specific pattern. This type of defect distribution is known as correlated disorder.

Alexei Vagov

'Imagine a crowd of people moving chaotically in different directions—that’s a classic example of disorder. Now imagine the same crowd moving in a complex but coordinated pattern, like a mass dance—that illustrates correlated disorder,' says Alexei Vagov, Professor at the HSE Tikhonov Moscow Institute of Electronics and Mathematics. 'In superconductors, it turns out that this kind of order within disorder causes defects to actually enhance superconductivity.'

In materials with defects, superconductivity typically develops in two stages. First, isolated regions appear where superconductivity begins to emerge. Then, as the temperature drops, these regions connect, allowing current to flow throughout the entire sample. Scientists have modelled a two-dimensional superconductor with varying defect distributions—from random to correlated, where impurities are interconnected. The results show that when disorder in the material is coordinated rather than chaotic, the transition happens immediately: superconductivity emerges simultaneously throughout the entire system.

The scientists believe these findings could aid in the development of thin superconducting films, whose structures closely resemble the model used in the study. When synthesising such films, it is possible to control the placement of defects in advance, which is useful both for testing the theory and for creating materials with specified properties. 

'Controlling the placement of defects at the microscopic level could enable the creation of superconductors that operate at much higher temperatures—potentially even at room temperature. This would transform superconductivity from a laboratory rarity into a technology used in everyday devices,' comments Alexei Vagov.

The study was conducted with support from the Ministry of Education and Science, Grant 075-15-2025-010, and HSE University's Basic Research Programme within the framework of the Centres of Excellence project.

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