Sergei Shevchenko, Leading Researcher.

Andrey Yanovskiy, Senior Researcher, PhD

shevchenko@ilt.kharkov.ua

Graduated from Kharkov Polytechnical Institute in 1964.

PhD Phys & Math (1970); DSc Phys & Math (1993).

Since 1971 has worked at ILTPE as a junior researcher, senior researcher (1976-1995)
from 1995 - leading researcher.
1985 - 1995 - professor at Kharkov State University
since 1995 - professor at Kharkov Polytechnical University.

Research areas:

Excitonic Superfluidity in Multilayer Electron Systems

The possibility of superfluidity in the systems with pairing of spatially separated carriers (SPSSC) in zero magnetic field was predicted by Shevchenko in 1976. Recent results obtained in this direction are as follows. It is shown that in SPSSC the quantum vortices can be induced by non-uniform magnetic and electric fields with nonzero two-dimensional divergence. The vortex patterns at certain field configurations are found. (Shevchenko, 1997, 2000). It is established that in superfluid systems in strong magnetic fields the vortices have an electric charge of order of the electron charge (Shevchenko, 2003). States with interlayer phase coherence in multilayer quantum Hall systems are studied. The conditions of stability of the phase coherent state relative to a transition to the charge ordered state are established. (Bezuglyj, Shevchenko, 2000; Shevchenko, Fil, Yakovleva, 2004). A new mechanism of binding of two equally charged carriers in double layer systems in a magnetic field of special form (magnetic fields in adjacent layer are equal in magnitude and opposite in direction) is proposed. (Shevchenko, Vol, 2003).

Interlayer tunnel conductivity of n-p bilayers with the electron-hole pairs in the Bose-Einstein condensed state was studied. A mechanism that explains a zero bias peak anomaly observed recently in bilayer quantum Hall systems is proposed. (Bezuglyj, Shevchenko, 2004).

Bose-Einstein Condensation

The Bogolyubov-de-Gennes equations for a two-dimensional Bose gas are derived. (Shevchenko, 1992). The exact solutions for the spectrum and eigenfunctions of elementary excitations in Bose gas in external potentials of special forms are found. (Fil, Shevchenko, 2001). The nondissipative drag in bilayer Bose systems is studied (Shevchenko, Terentjev, 1999; Fil, Shevchenko, 2005).

Thermoelectric effects in superfluid systems

It is predicted that oscillations of temperature during propagation of third sound in a thin superfluid film cause appearance of an alternating electric field in the surrounding space (a peculiar non-stationary thermoelectric effect). It is shown that the differential thermal EMF (the ratio of electric potential amplitude to the film temperature amplitude) can exceed such one in metals (Shevchenko, Konstantinov, 2016, 2019).

Selected publications:

  1. S. I. Shevchenko, Theory of superconductivity in the systems with pairing of spatially separated electrons and holes. FNT 2, 505 (1976).
  2. S. I. Shevchenko, On the Theory of a Bose Gas in a Nonuniform Field, FNT 18, 328 (1992).
  3. S. I. Shevchenko, Polarizable Quantum Systems in Crossed Electric and Magnetic Fields, Phys. Rev. Lett. 75, 3312 (1995).
  4. S. I. Shevchenko, Vortices and Vortical Structures in Systems with Pairing of Spatially Separated Electrons and Holes, PR B 56, 10355-10368 (1997),
  5. S. V. Terentjev, S.I. Shevchenko, On Transfer of Motion in a System of Two-Dimensional Superfluid Bose-Gases Separated by a Thin Layer, Low Temp. Phys. 25, 493 (1999).
  6. V. A. Bezugly, S.I.Shevchenko, Spontaneous Interlayer Coherence in Multilayer Electron Systems in Strong Magnetic Fields, Physica B, 284-288, 1205 (2000).
  7. S. I. Shevchenko, On Vortices Induced in Superfluid Films by Crossed Electric and Magnetic Fileds, J. Low Temp. Phys. 121, 429 (2000).
  8. D. V. Fil, S. I. Shevchenko, Collective Excitations of a Two-Dimensional Interacting Bose Gas in External Fields, Phys. Rev. A 64, 013607 (2001).
  9. S. I. Shevchenko, E. D. Vol, Metastable Bound State of a Pair of Two-Dimensional Spatially Separated Electrons in Anti-Parallel Magnetic Fields, J. Phys.: Condens. Matter, 15, 8455 (2003).
  10. S. I. Shevchenko, Charged Vortices in Superfluid Systems with Pairing of Spatially Separated Carriers, Phys. Rev. B 67, 214515 (2003).
  11. A. I. Bezuglyj, S. I. Shevchenko, Order Parameter Phase Locking as a Cause of a Zero Bias Peak in the Differential Tunneling Conductance of Bilayers with Electron-Hole Pairing, Low Temp. Phys. 30, 208 (2004).
  12. S. I. Shevchenko, D. V. Fil, A. A. Yakovleva, Charge Ordering and Interlayer Phase Coherence in Quantum Hall Superlattices, Low Temp. Phys. 30, 321 (2004).
  13. D. V. Fil, S. I. Shevchenko, Nondissipative drag of superflow in a two-component Bose gas, Phys. Rev. A 72(1), 013616 (2005).
  14. A. I. Bezuglyj, S. I. Shevchenko, Polarizable Quantum Systems in Crossed Electric and Magnetic Fields, Phys. Rev. B 75, 075322 (2007).
  15. S. I. Shevchenko, A. S. Rukin, On the electrical activity of superfluid systems, JETP Letters 90, 42 (2009).
  16. A. I. Bezuglyj and S. I. Shevchenko, Oscillations of an electron-hole pair condensate in excitonic traps, Low Temp. Phys. 35, 373 (2009).
  17. S. I. Shevchenko and A. S. Rukin, On electrical phenomena in electroneutral superfluid systems, Low Temp. Phys. 36, 146 (2010).
  18. S. I. Shevchenko and A. S. Rukin, On the electric polarization of inhomogeneous superfluid systems, Low Temp. Phys. 36, 596 (2010).
  19. A. S. Rukin and S. I. Shevchenko, On electric fields created by quantized vortices, Low Temp. Phys. 37, 884 (2011)
  20. S. I. Shevchenko and A. S. Rukin, Two approaches to the description of dilute superfluid Bose systems, Low Temp. Phys. 38, 905 (2012).
  21. S. I. Shevchenko, On the possibility of vortex creation in superfluid systems by crossed homogeneous magnetic and inhomogeneous electric fields, Low Temp. Phys. 39, 319 (2013).
  22. S. I. Shevchenko, A.M. Konstantinov, On the Dipole Moment of Quantized Vortices in the Presence of Flows, J. Low Temp. Phys. 185, 384 (2016).
  23. S. I. Shevchenko, A.M. Konstantinov, On the Possibility of a New Electric Effect in Ultrathin Superfluid Films, JETP Letters, 104, 489 (2016).
  24. D. V. Fil, S. I. Shevchenko, Electron-hole superconductivity, Low Temp. Phys. 44(9), 867 (2018).
  25. S. I. Shevchenko, A.M. Konstantinov, Non-stationary Thermal Electromotive Force Generated by Third Sound, J. Low Temp. Phys. 194, 1 (2019).
  26. S. I. Shevchenko, A.M. Konstantinov, Heat Superconductivity and Electrical Activity of Superfluid Systems, JETP Letters, 109, 790 (2019).
  27. D. V. Fil, S. I. Shevchenko, Transition to a supersolid phase in a two-dimensional dilute gas of electron-hole pairs, Low Temp. Phys. 46, 465 (2020).