Research area:

Lattice Dynamics, phonons and other quasi-particle excitations in solids:

• Propagation and localization of vibrations in ill-ordered crystals, heterogeneous structures and disordered systems
• Vibrational characteristics of crystals with complex defects;
• Dynamics of complex crystal lattices, strongly anisotropic crystal structures, and quasi-low-dimensional lattices.
• Computer modeling of complex crystal structures and disordered systems.

(See also: A.M. Kosevich research group)

Main achievements:

• The main distinctive peculiarities of phonon spectra of strongly anisotropic layered and chain crystals were determined and systemized (with E.S. Syrkin); the effect of these peculiarities on the behaviour of oscillatory thermodynamics characteristics of this kind of compositions was studied, in particular, there was defined a microscopic theory of the so-called "membrane effect".
• Propagation and localisation characteristics of oscillations in lattices of various dimensions were studied and a new method for the localized states description based on J-matrix was suggested.
• A number of microscopic calculations on the atomic dynamics of the definite crystal structures both perfect and defected were made.
• Phonon spectra behaviour of crystals with the weakened effect of crystal atoms ordering regularity (systems with complex defects, multi-layered structures of HTSC-type, nanoclusters, etc.) was investigated on microscopic level; it was found that the oscillatory characteristics of such compositions were definitely conditioned by its strong spatial nonhomogeneity as well as the local anisotropy of interatomic interaction. (with E.S. Syrkin and A.M. Kosevich)
• Localization and propagation of vibrations in heterogeneous crystals and disordered solid solutions
• Creation of calculation models for investigation of electron and phonon spectra of graphite and carbonic nanostructures.

Main Publications:

1. S.B.Feodosyev, I.A.Gospodarev, E.S.Syrkin, Anomalies of Linear Expansion Coefficient in Highly Anisotropic Crystals at Low Temperature, Phys, Stat. Sol (b), 150, K19, 1988.
2. I.A.Gospodarev, S.B.Feodosyev, A.P.Isakina, A.I.Prokhvatilov, E.S.Syrkin, Effect of the Crystalline Structure Anisotropy of the High Temperature Superconductor Bi2Sr2CaCu2Ox on its Thermal Expansion ФНТ, 16, 673 1990.
3. S.B. Feodosyev, I.A. Gospodarev, A.M. Kosevich, E.S. Syrkin, Quasi-Low-Dimensional Effects in Vibrational Characteristics of 3D-Crystals, Phys. Low Dim. Str., 10/11, 209, 1995.
4. I.A. Gospodarev, A.V. Grishaev, E.S. Syrkin, S.B. Feodosyev, Local Vibrations of FCC-Crystals with Two Parametric Substitution Impurities. Phys. Solid State,42 (12), 2000.
5. A.M. Kosevich, A. Mayer, S.B. Feodosyev, I.A. Gospodarev, V.I. Grishaev, E.S. Syrkin, Atom Dynamics of Micro-Clusters on Atomically Smooth Surfaces, Superlattices and Microstructures, 27 ( 1), 7, 2000.

6. S.B. Feodosyev, I.A. Gospodarev, M.A. Strzhemechny, R.J. Hemley, Phonon Assisted Ortho- Para Conversion in Solid H₂ Under Pressure, Physica B: Physics of Condensed Matter, 300, 186, 2001.
7. E.T. Verkhovtseva, I.A. Gospodarev, A.V. Grishaev, S.I. Kovalenko, D.D. Solnyshkin, E.S. Syrkin, S.B. Feodosyev, Atom Dynamics and the Problem of the Structural Stability of Free Clusters of Solidified Inert Gases, Low Temperature Physics, 29(5), 386, 2003.
8. I.A. Gospodarev, V.I. Grishaev, O.V. Kotlyar, K.V. Kravchenko, E.V. Manzhelii, E.S. Syrkin, and S.B. Feodosyev, Ioffe–Regel crossover and boson peaks in disordered solid solutions and similar peculiarities in heterogeneous crystal structures Low Temperature Physics, 34 (8), 655, 2008.
9. I.A. Gospodarev, K.V. Kravchenko, E.S. Syrkin and S.B. Feodos’ev Quasi-two-dimensional features in the phonon spectrum of graphite Low Temp. Phys. 35 (7) 589, 2009.
10. A. Feher, I.A. Gospodarev, V.I. Grishaev, K.V. Kravchenko, E.V. Manzheliĭ, E.S. Syrkin and S.B. Feodos’ev, Effect of defects on the quasiparticle spectra of graphite and graphene, Low Temp. Phys. 35 (8), 679, 2009.
11. I.K. Galetich, I.A. Gospodarev, V.I. Grishaev, A.V. Eremenko, K.V. Kravchenko, , V.A. Sirenko, S.B. Feodosyev, Vibrational characteristics of the niobium dichalcogenide. Bulk samples and nanofilms, Superlattices and Microstructures, 45 (6), 564, 2009
12. I.A. Gospodarev, V.V. Eremenko, K.V. Kravchenko, V.A. Sirenko, E.S. Syrkin and S.B. Feodos’ev. Vibrational characteristics of niobium diselenide and graphite nanofilms Low Temp. Phys. 36 (4), 344, 2010.
13. Alexander Feher, Eugen Syrkin, Sergey Feodosyev, Igor Gospodarev and Kirill Kravchenko. Quasi-Particle Spectra on Substrate and Embedded Graphene Monolayers, In: “Physics and Application of Graphene – Theory” (ed. S. Mikhailov) ISBN 978-953-307-996-7, InTech Open Access Publisher, Croatia, pp.93-112, 2011.
14. A Feher, E. Syrkin, I. Gospodarev, E. Manzhelii, A. Kotlyar, K. Kravchenko, The Features of Low Frequency Atomic Vibrations and Propagation of Acoustic Waves in Heterogeneous Systems. In: “Waves in Fluids and Solids” (ed. Ruben Pico Vila) ISBN 978-953-307-285-2, InTech Open Access Publisher, Croatia, pp. 103-126, 2011.
15. Feodosyev S.B., Gospodarev I.A., Grishaev V.I., Kotlyar O.V., Kravchenko K.V., Manzhelii E.V., Syrkin E.S., Yeremenko A.V., Galetich I.K. Low Temperature Peculiarities of Quasi-Particle Spectra of Disordered Solid Solutions. In: “Contemporary Problems of Mathematics, Mechanics and Computer Sciences” (eds. N.N. Kizilova, G.N. Zholtkevich) ISBN 978-966-2579-92-5 Kharkov: Publishing house PPB Virovec A.P., Ukraine, pp. 51-62, 2011
16. A.Feher, I.Gospodarev, O.Kotlyar, K.Kravchenko, E.Manzhelii, E.Syrkin, S.Feodosyev Impurity levels in the electron spectra of graphene, Superlattices and Microstructures, 53, 55, 2013
17. A. Feher, E. Syrkin, S. Feodosyev, I. Gospodarev, E. Manzhelii, A. Kotlar and K. Kravchenko. Electronic and Vibrational Properties of Adsorbed and Embedded Graphene and Bigraphene with Defects. In: New Progress on Graphene Research. Ed. Jian Ru Gong, InTech, Rijeka, Croatia, ISBN 978-953-51-1091-0, pp. 135-158 (2013)
18. I.A. Gospodarev, A.V. Eremenko, K.V. Kravchenko, A.F. Sirenko, V.A. Sirenko, E. S. Syrkin, S.B. Feodosyev, and Yu. A. Shabakaeva, Distinctive Features of Thermal Expansion of Niobium Diselenide, Physics of the Solid State, 55 (4), 825, 2013
19. E.V. Manzhelii, S.B. Feodosyev, I.A. Gospodarev, E.S. Syrkin, K.A. Minakova Phonon spectrum and vibrational characteristics of linear nanostructures in solid matrices Low Temperature Physics 41 (7), 557-562, 2015
20. V.V. Eremenko, V.A. Sirenko, I.A. Gospodarev, E.S. Syrkin, S.B. Feodosyev I.S. Bondar, K.A. Minakova Effect of step-edge on spectral properties and planar stability of metallic bigraphene Low Temperature Physics 42 (2), 99-105, 2016
21. V.V. Eremenko, A.F. Sirenko, V.A. Sirenko, A.V. Dolbin, I.A. Gospodarev, E.S. Syrkin, S.B. Feodosyev, I.S. Bondar, K.A Minakova Role of acoustic phonons in the negative thermal expansion of layered structures and nanotubes based on them Low Temperature Physics 42 (5), 401-410, 2016
22. V.V. Eremenko, V.A. Sirenko, I.A. Gospodarev, E.S. Syrkin, S.B. Feodosyev, I.S. Bondar, K.A. Minakova Anisotropic behavior and inhomogeneity of atomic local densities of states in graphene with vacancy groups Journal of Science: Advanced Materials and Devices 1 (2), 167-173, 2016
23. A. Feher, S. Feodosyev, I. Gospodarev, E. Syrkin, and V. Grishaev. Phonon Spectrum and Vibrational Thermodynamic Characteristics of Graphene Nanofilms. In: Graphene Science Handbook: Nanostructure and Atomic Arrangement. CRC Press, ISBN 9781466591370, 289-304, 2016
24. Eremenko V., Sirenko V., Dolbin V., Feodosyev S., Gospodarev I., Syrkin, Bondar I., Minakova K The Phonon Mediated Anomalies of Thermal Expansion in Transition-Metal Componds and Emergent Nanostructures. "Solid State Phenomena. 257 (1), 81-85, 2017
25. I.A. Gospodarev, V.I. Grishaev, E.V. Manzhelii, E.S. Syrkin, S.B. Feodosyev, K.A. Minakova. Phonon heat capacity of graphene nanofilms and nanotubes. Low Temperature Physics 43 (2), 264-273, 2017.
26. V.V. Eremenko, V.A. Sirenko, I.A. Gospodarev, E.S. Syrkin, S.B. Feodosyev, I.S. Bondar, Feher A., K.A Minakova. Electron and phonon states localized near the graphene boundary. Low Temperature Physics 43 (11), 1323-1331 (2017)
27. V.V. Eremenko, V.A. Sirenko, I.A. Gospodarev, E.S. Syrkin, S.B. Feodosyev, I.S. Bondar, K.A Minakova, Feher A. Electron spectra of graphene with local and extended defects. Journal of Physics: Conference Series 969 (1), 012021 (2018)
28. E.V. Manzhelii, S. B. Feodosyev, and I.A. Gospodarev, Phonon spectra and vibrational heat capacity of quasi-one-dimensional structures formed by rare gas atoms on the surface of carbon nanotube bundles, Low Temp. Phys., 45 (3), 355 (2019)
29. I.A. Gospodarev, V.I. Grishaev, E.V. Manzhelii, V.A. Sirenko, E.S. Syrkin, Effect of size quantization upon electron spectra of graphene nanoribbons, Low Temp. Phys., 46 (2), 231-240 (2020)
30. I.A. Gospodarev, V.A. Sirenko, E.S. Syrkin and K.А. Minakova, Low-dimensional peculiarities of vibrational characteristics and stability of graphene nanostructures (Review article), Low Temp. Phys., 46 (3), 286-315 (2020)