Centre for Quantum Metamaterials - 2023 Results

11 scientific articles have been published in Q1 journals, including Nature Physics and Physical Review Letters. The research results were also presented in 17 reports at leading international scientific (scientific and practical) conferences in the Russian Federation and abroad.

A series of joint studies with the Center for Advanced Methods of Mesophysics and Nanotechnology, MIPT, within the framework of a large grant from the Russian Academy of Sciences "Superconducting Functional Materials for Advanced Quantum Technologies" were launched.

The cooperation agreements with the Brazilian Federal Universities of Pernambuco and Rio de Janeiro has been negotiated and prepared for signing. Also the  online school  in cooperation with Brazilian universities  has benn organized.

A scientific visit of Dr. Mauro Doria, Professor at the Federal University of Rio de Janeiro, was successfully organized, during which lectures, seminars and scientific discussions were held for students, postgraduates and researchers at the Higher School of Economics.

The Chief researcher of the Center, Professor A.A. Shanenko and the Director of the Center, Professor A.V. Vagov took part in the first Russian-Chinese school for students, postgraduates and undergraduates, on the basis of MIPT.

Scientific results of the center:

The main purpose of the theoretical research of the Center for Quantum Metamaterials was to study the quantum properties of metamaterials and their relationship to various system characteristics such as reduced dimensionality, the presence of impurities, details of the band structure and other factors.
Quantum states in phosphorene monolayers have been studied. It is shown that such systems are semi-Dirac materials, the carriers of which behave relativistically in one direction and non-relativistically in the other. The influence of band anisotropy on the physical properties of such semi-Dirak materials, including magnetotransport, optical conductivity, dielectric function and thermoelectric characteristics, has been studied. [F.M. Peeters, together with colleagues from Iran]

The thermoelectric properties of phosphorene nanocells were calculated in the presence and absence of a perpendicular magnetic field. Our results suggest that such nanocircles are promising nanostructures for thermoelectric applications. [F.M. Peeters, together with colleagues from Iran]

The interaction of superconductivity and ferromagnetism within the framework of a single compound has been studied. The existence of a temperature window located between the Curie temperatures and the critical temperature of the superconducting transition, where these ferromagnetic superconductors are in the intertype mode, is proved. A phase diagram of this system is obtained, characterized by exotic configurations of spatial flows - vortex clusters, chains, giant vortices and vortex liquid droplets - which are absent in bulk superconductors of both type I and II. It is shown that the intertype mode practically does not depend on microscopic parameters and can be achieved by simply changing the temperature. The results open the way for detailed experimental studies of the hitherto little-studied intertype superconductivity. [A.V. Vagov, A. A. Shanenko, together with colleagues from Russia, Brazil and France]

The phenomenon of dynamic self-organization of vortex matter in transient superconductors under the influence of a magnetic field, temperature and an external current is investigated. The results obtained completely coincided with the experimental data for known Nb and similar materials [A.V. Vagov, A.A. Shanenko, together with colleagues from Germany, France and Brazil].

By studying the spatial configurations of the intermediate mixed state in an intertype superconductor, it is shown that the clustering of vortices can be characterized by the averaged distribution of the magnetic field in the sample. Clustering manifests itself in the two-peak structure of this distribution. The result is general in nature and does not depend on the details of the model. [A.V. Vagov, E.G. Nikonov]

The behavior of vortex matter near the crossover of the I-II kind of superconductivity is studied by modeling the molecular dynamics of vortices in the transient mode. The transition of a homogeneous vortex lattice into a structure consisting of domains with and without vortices is investigated. The calculation results show the stability of such a transition and at the same time a strong dependence on the external magnetic field. [A.V. Vagov, together with colleagues from Germany]

Within the framework of the Bogolyubov-de Genet theory, the effect of the surface potential on the critical temperature of the superconducting transition on the sample surface is described. The surface details are taken into account within the framework of the effective potential of Langakon. It is shown that the superconductivity of a sample can be controlled using the properties of its surface. [M. Kroitoru, A.A. Shanenko, together with colleagues from France]

The influence of impurities with a correlated location in space on superconducting properties is investigated. Numerical calculations within the framework of microscopic theory have shown that spatial correlations of impurities have completely different effects on the so-called local and global properties of a superconductor. Thus, the degree of correlations can be used as another parameter of superconductivity control. [V.D. Neverov, A.E. Lukyanov, A.V.Krasavin, A.V. Vagov, M. Kroitoru]

The behavior of the Cooper pair wave function in a normal metal near the metal-superconductor surface is investigated. The results showed that the multi-zone nature of superconductivity significantly affects the degree of attenuation of the wave function in a normal metal. It is shown that the effect strongly depends on the Fermi level. This result makes it possible to configure such transitions for practical applications. [M. Kroitoru, A. A. Shanenko, together with colleagues from China]

It was also investigated how the applied electric field affects the interference surface superconductivity. The study is based on the numerical solution of the self-consistent Bogolyubov-de Genet equations for the one-dimensional attractive Hubbard model. The results showed that the characteristics of surface superconductivity vary greatly depending on the applied field. An electric field can cause phase transitions between superconducting, metallic and insulating states in thin-film materials due to changes in the density of charge carriers. [M. Kroitoru, A.A. Shanenko, together with colleagues from China and Brazil]

The role of quantum interference on surface superconductivity is investigated. It is shown that such an increase can be very significant and reach 70%. Moreover, it is observed in a very wide range of microscopic parameters of the material. [M. Croitoru, together with colleagues from Brazil]

The effect of surface plasmon generation on the reflection of light from a thin conductive plate is investigated. It has been shown that such generation leads to a significant increase in light absorption in the visible range [A.V. Vagov, M. Kroitoru together with colleagues from Germany and Russia]

A technique for processing noisy spectral data has been developed, which makes it possible to implement mathematically justified selection of sharp peaks of the signal on an unknown smooth background, for which there is no reliable theoretical model. The proposed approach provides an algorithm for processing experimental data that allows filtering out random noise and determining both peak parameters and the background function with good accuracy. [A.V. Vagov, together with colleagues from Russia]