Main scientific results in 2022  year    

V3S4 - A new two-dimensional nanomaterial promising for applications in sensors

New generation gas sensors are characterized by high efficiency and low power consumption, so the search for two-dimensional materials suitable for use as magnetic gas sensors at room temperature is a critical task for modern materials science. 
In our work, we have predicted an ultrathin two-dimensional antiferromagnetic material V3S4, which, in addition to stability and unique electronic properties, shows great potential for magnetic sensor applications. The results of quantum mechanical calculations indicate the antiferromagnetic ground state V3S4, which exhibits semiconductor electronic properties with a band gap of 0.36 eV. The results of the studies also indicate a significant electronic and magnetic response to the adsorption of NH3, NO2, O2, and NO molecules on the surface of V3S4. The results showed the promise of using V3S4 as a new generation sensor material for the detection of NO2 and NO, as well as in oxygen reduction reactions. It should be noted that the detection and reduction of NO2 and NO are of great importance for the conservation of environmental conditions.

The work was published in the journal Nanomaterials (IF=5.346, DOI:  10.3390/nano12050774)

The work was supported by a grant  RFBR № 20-53-05009 Arm_a

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  The main scientific results in 2021    

New two-dimensional structure from fragments of metallocene molecules

Organometallic compounds attract the attention of researchers due to their unique physicochemical properties. One of the best known organometallic compounds is metallocene molecules.

In our work, we proposed new stable sandwich two-dimensional metallocene-like structures, which were named t-MCp2 and m-MCp2. The calculation of the electronic structure showed that the iron-containing structures exhibit semiconducting properties, and the cobalt-containing structures exhibit the properties of semimetallic ferromagnets. The study of the optical properties of the new structures showed the appearance of peaks in the UV region and in the visible range of light in comparison with pure carbon structures, which indicates the possibility of using such compounds in photoinduced catalytic reactions, since in the structures considered, the metal atom in the carbon lattice can change its oxidation state. which is especially important for these reactions.

The work was published in the journal Carbon (IF = 9.594, DOI:  https://doi.org/10.1016/j.carbon.2021.08.074)

This work was supported by a grant  Russian Science Foundation No. 21-73-20183

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Diaman quasicrystals

Quasicrystals are structures with quasiperiodic ordering without spatial periodicity. Quasicrystals have been of great interest to researchers since their discovery by Dan Shechtman in 1984 due to their unique three-dimensional structures and their properties. Since the discovery, the existence of hundreds of quasicrystals of various compositions has been reported and confirmed.  

In our work, we studied the first two-dimensional carbon quasicrystal completely consisting of sp3-hybridized atoms, namely, a diamane quasicrystal.

This nanostructure is based on an incommensurate lattice of two graphene layers rotated relative to each other at an angle of 30 ° with fully hydrogenated or fluorinated surfaces. Here hydrogenation / fluorination of the layers leads to the formation of interlayer covalent bonds.  

In this work, a detailed analysis of the features of the atomic structure of a quasicrystal is carried out. Thermodynamic stability, as well as electronic and mechanical properties were studied by DFT and MD methods. Comparison with periodic approximants and AB-diamans shows that the quasicrystalline structure is harder and more brittle.
Our study shows that quasicrystalline diamane is a promising material that opens a new path to the synthesis of inorganic quasicrystals of various compositions with a unique set of physicochemical properties.
The results of the work were published in the journal Applied Surface Science (IF - 6.707, DOI: https://doi.org/10.1016/j.apsusc.2021.151362 ).

Manipulating the charge of a single atom opens up new prospects for creating high-capacity spin electronics and memory devices. The main problem is the ordering of metal atoms wich can change their charge  on the surface of the material. Previously, for these purposes, artificial deposition of metal atoms on a dielectric substrate was used. In work under the leadership of Corresponding Member of RAS Streltsov Sergei Vladimirovich (USU RAS) colleagues from the USA, China and our team studied the NbS2Co1/3 crystal, which is niobium disulfide layers intercalated with cobalt atoms. The splitting of such a crystal reveals the NbS2 surface covered with an ordered layer of cobalt atoms.

It was shown that, by applying a pulse to the tip of a tunnel microscope, it is possible to transfer selected metal atoms into a long-lived metastable state, the detection of which is also possible using tunnel microscopy methods. In this case, it is also possible to perform the reverse switching of metal atoms to the ground state.
The verification of the experimentally obtained microscopic images of atomic resolution was carried out using the methods of computer simulation. A study within the framework of the theory of the electron density functional showed that the stabilization of metastable states is possible due to the changed crystal field on the NbS2 surface. The results obtained open up prospects for further research of intercalated materials for use in spin electronics and high-density data storage devices.
The results of the work were published in the journal Nano Letters  ( IF = 11.189 , DOI: 10.1021 / acs.nanolett.1c03706 ).

Intramolecular transistor based on single-walled CNTs

An intramolecular transistor based on single-walled carbon nanotubes (CNTs) has been created. The use of strong heating and mechanical deformations in a controlled mode made it possible to locally change the chirality of individual CNTs inside a transmission electron microscope. Stretching of a heated metal CNT led to a change in the chirality of the CNT segment, which became a semiconductor, thus creating an intramolecular nanotube transistor. The transistor channel length was only 2.8 nm.

In the transistors obtained, coherent quantum interference of electrons was observed at room temperature, which means the appearance of energy barriers at the contact points of the metal and semiconductor CNTs. The observed effects are analogous to interference at the atomic level, and the resulting device is a quantum Fabry – Perot interferometer.

The results of the work indicate the prospects for a controlled change in the chirality of single-walled carbon nanotubes, which solves the most important problem of this nanomaterial and brings closer the practical application of these nanostructures to create unique nanotransistors and, subsequently, new-generation processors without the use of silicon.

The research results were published in the journal Science ( IF = 41.845 , DOI: 10.1126 / science.abi8884 )

Intramolecular transistor based on single-walled CNTs

Since the synthesis of graphene, an extremely interesting task of modern materials science has been to obtain a new two-dimensional material with controlled properties. A successful attempt to create such a material can be called the synthesis of boron oxynitride (BNO), which combines the structure (atomic and electronic) of hexagonal boron nitride and impurity oxygen atoms.

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The first works on the synthesis of BNO indicated that the oxygen atoms in such a material are in the position of substitution of nitrogen atoms, however, recent studies have shown that the introduction of oxygen can change the hexagonal crystal structure of boron nitride, which leads to the appearance of new electronic properties of this material. Studies have shown that doping with oxygen leads to the formation of specific two-dimensional materials with a more defective and less dense structure. This is due to the fact that the arrangement of oxygen atoms to form an epoxy bridge is an energetically favorable position at a certain concentration compared to the substitution position. This also led to the appearance of local dipole moments, which can give the structure unusual piezoelectric properties, in other words, the probability of the appearance and amplification of electrical impulses under mechanical action increases.

The results of studies of the new two-dimensional structure of BNO are of practical importance in nano- and optoelectronic devices, such as solar energy converters and flexible electronics.

The work was published in the journal Physical Chemistry Chemical Physics (IF=3.676, DOI: 10.1039/D1CP03754D)
This work was supported by the Russian Science Foundation grant No. 21-73-10238 and the President of the Russian Federation grant for the state support of young Russian scientists and the state support of the leading scientific schools of the Russian Federation MK-3120.2021.1.2.

   The main scientific results in 2020   

Hexagonal NaCl on a diamond substrate

The evolutionary algorithm was the first to predict the possibility of the formation of a graphene-like NaCl layer on a diamond surface. In collaboration with scientists from Moscow State University and Skoltech, an experimental synthesis of such objects was carried out.

It was shown that due to the strong bond between the film and the diamond substrate, as well as the presence of a wide band gap, hexagonal NaCl can be effectively used as a dielectric to protect the gate in diamond field-effect transistors from breakdown, which, in turn, have broad prospects for practical application. in electric vehicles, radars, etc. Comparison between experimental and theoretical data of electron diffraction and X-ray spectroscopy confirmed the existence of a new material based on NaCl with a hexagonal structure.

The work was published in The Journal of Physical Chemistry Letters (IF = 6.71, DOI: https://doi.org/10.1021/acs.jpclett.0c00874)

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Multilayer structures of alkali metals in bilayer graphene and MoS2: a theoretical modeling

Researchers of our group (Z.I. Popov), together with an international team of scientists from MISiS (Russia), HZDR (Germany), Max Planck Institute (Germany), conducted a theoretical study of the formation of alkali metal structures in the interlayer space of bilayer graphene and MoS2 monolayer.

It was shown that the capacity of the predicted structures (mA∙h∙g-1) exceeds the theoretical capacity of graphite (372 mA∙h∙g-1).
It was also found that multilayer sodium structures in two-layer graphene are more stable than single-layer ones.

The work was published in Nano Energy (IF = 16.602, DOI: https://doi.org/10.1016/j.nanoen.2020.104927 )

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New Composite of Graphene and Heusler Alloy Co2Fe (Ga0.5Ge0.5) for High-Performance Spintronic Devices

The material considered in the work seems to be promising for magnetic memory devices with increased recording density. Previously, graphene was not used in magnetic memory devices.


In the presented work, it was possible to obtain a new heterostructure (graphene/Heusler alloy), which demonstrates several surprising features, such as the quasi-free nature of graphene and the retention of the semi-metallic band structure of the Heusler alloy at the interface. This work offers a new perspective on the future development of advanced spintronic storage devices.

Synthesis and experimental research was carried out in collaboration with National Institutes for Quantum and Radiological Science and Technology QST (Japan).

The article was published in the journal Advanced Materials (IF = 27.398, DOI: https://doi.org/10.1002/adma.202070043 )

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Spin polarization in graphene/MoX2* heterostructures (X = S, Se; * = F, Cl, Br, I)

Magnetic halogen doped MoX2 (X = S and Se) monolayers influenced the electronic structure of graphene through a proximity effect. This process was observed using state-of-the-art calculations. Detailed analysis of halogen doped MoX2/graphene heterostructures demonstrated the induction of spin polarization in graphene near the Fermi energy. Significant spin polarization near the Fermi energy and n-type doping were observed in the graphene layer of MoSe2/graphene heterostructures with MoSe2 doped with iodine. At the same time, fluorine-doped MoSe2 does not cause n-doping in graphene, while spin polarization still takes place. The possibility for the detection of the arrangement of the halogen impurities at the MoX2 basal plane even with the graphene layer deposited on top was demonstrated through STM measurements which will be undoubtedly useful for the fabrication of electronic schemes and elements based on the proposed heterostructures for their further application in nanoelectronics and spintronics.

The article was published in Nanoscale (IF = 6.895, DOI: https://doi.org/10.1039/D0NR06287A)

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Controlling the Optical Properties of Bilayer Graphene Nanomeshes by Applying External Mechanical Deformations

We present an ab initio study of ways for engineering electronic and optical properties of bilayered graphene nanomeshes with various stacking types via mechanical deformations. Strong evolution of the electronic structure and absorption spectra during deformation is studied and analyzed. The obtained results are of significant importance and open up new prospects for using such nanomeshes as materials with easily controlled properties in electronic and optoelectronic nanodevices.

The article was published in ACS Applied Materials & Interfaces (IF = 8.758, DOI: https://doi.org/10.1021/acsami.0c17060)

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