B. Verkin Institute for Low Temperature Physics and Engineering National Academy of Science (NAS) of Ukraine


Head of the Department  
Prof. Naidyuk Yurii Georgievich
Tel : +(380)-57-3402211, Fax: +(380)-57-3403370, +(380)-57-3450593, e-mail: naidyuk at ilt.kharkov.ua


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Point-contact spectroscopy of electron-quasiparticle interaction


Bashlakov D.L. bashlakov at ilt.kharkov.ua 
Bobrov N.L. bobrov at ilt.kharkov.ua 
Khotkevich A.V. khotkevich at ilt.kharkov.ua
Kvitnitskaya О.E. kvitnitskaya at ilt.kharkov.ua 
Naidyuk Yu.G. naidyuk at ilt.kharkov.ua 


Main research:

  • point-contact spectroscopy of electron-quasiparticle interaction in rare-earth nickelborocarbides, magnesium diboride, high-temperature and iron-based superconductors;

  • investigation of the nonequilibrium, non-stationary and thermal effects in the conductivity of metallic nanocontacts;
  • observation and investigation of quantum effects in conductivity of 3-D metallic nanocontacts.

Main results:

Atlas of electron-phonon-interaction functions for more than 30 metals was published.

Sign reverse of the point-contact spectra in semimetals due to the strong localization was observed.

Electron-phonon interaction spectra of rare-earth nickel-borocarbide compounds were investigated. A low frequency mode and crystal-electric field effects in  rare-earth nickel-borocarbide compounds were detected.

Detection of anisotropy of electron-phonon interaction in MgB2.

Discovery of the Kondo-effect in point contacts with magnetic impurities and observation of the Kondo-size effect.

High-frequency point-contact spectroscopy has been developed to study the relaxation kinetics of quasiparticle excitations in solids: high-energy phonons, two-level systems, crystal-field levels.

Displacement method for point-contact creation was proposed and original mechanism was constructed for point-contacts creation.

The possibility of investigation of the intramolecular vibrations in organic conductors by the point-contact spectroscopy method is shown. The anisotropy of point-contact spectra of organic conductors is detected.
Point-contact spectra, showing electron-phonon interaction effects, destruction of localization of an electronic states and the transition to a state with charge density wave (CDW) in layered quasi-2D dichalcogenides 1T-VSe2 and 2Ha-TaSe2, were obtained. The unknown before main parameters of the CDW state for 1T-VSe2 compound - the Coulomb potential, densities of states at the Fermi level and deformational potential, were defined. The function of electron-phonon interaction in these compounds was defined.



The point-contact spectrometers for investigation of nonlinear conductivity of contacts. Such spectrometers have a cryogenic equipment for creation of point contacts and measuring of CVC, the first and the second derivatives of CVC for point contacts
in temperature interval 0.8-77 K and magnetic field 0-9T.

International collaboration:

- Institut des Matériaux Jean Rouxel, France

- Institute of Experimental Physics, Kosice, Slovak Republik

- Leibniz Institute for Solid State and Materials Research, Dresden, Germany

- Physical Institute University of Karlsruhe, Karlsruhe, Germany

- Texas A&M University, College Station, USA

Reviews, principal and recent publications:

  1. Yu. G. Naidyuk, O.E. Kvitnitskaya, L. V. Tiutrina, I.K.Yanson, G. Behr, G. Fuchs, S.-L. Drechsler, K. Nenkov, and L. Schultz, Peculiarities of the superconducting gaps and the electron-boson interaction in TmNi2B2C as seen by point-contact spectroscopy, Phys. Rev. B, 2011,  Vol. 84, p.094516

  2. G.V.Kamarchuk, A.V.Khotkevich, A.V. Savitskii P. Molinié, A. Leblanc, E. Faulques. Electron-phonon interaction function in the layered dichalcogenide 2Ha TaSe2. Low Temp. Phys., 2009, Vol.35, p.539.

  3. Yu. G. Naidyuk, O. E. Kvitnitskaya, I. K. Yanson, G. Fuchs, K. Nenkov, A. Waelte, G. Behr, D. Souptel, and S.-L. Drechsler, Point-contact spectroscopy of the antiferromagnetic superconductor HoNi2B2C in the normal and superconducting state, Phys. Rev. B, 2007, Vol. 76, p.014520.

  4. D. L. Bashlakov, Yu. G. Naidyuk, I. K. Yanson, G. Behr, S.L. Drechsler, G. Fuchs, L. Schultz and D. Souptel, Point-contact spectroscopy of the nickel borocarbide superconductor YNi2B2C in the normal and superconducting stateJ. Low Temp. Physics, 2007,  Vol.147, p.335.

  5. G.V. Kamarchuk, A.V. Khotkevich, V.M. Bagatsky, V.G. Ivanov, P. Molinié, A. Leblanc, E.C. Faulques, Direct determination of Debye temperature and electron-phonon interaction in 1T-VSe2, Phys. Rev. B, 2001, Vol. 63, p.073107.

  6. Yu.G. Naidyuk, I.K. Yanson, Point-contact spectroscopy of the heavy-fermion systems (review). J. Phys. Condens. Matter, 1998, Vol.10, p.8905.

  7. O.P. Balkashin, R.J.P. Keijsers, H. van Kempen, Yu.A. Kolesnichenko, O.I. Shklyarevskii. Relaxation of two-level fluctuators in point contacts, Phys. Rev. B, 1998, Vol.58, p.1294

  8. O.P. Balkashin, A.G.M. Jansen, U. Gottlieb, O. Laborde, R. Madar Electron-phonon-interaction spectra of TaSi2, NbSi2 and VSi2, Solid State Commun. 1996, Vol.100, p.293

  9. G.V. Kamarchuk, A.V. Khotkevich, Yu.A. Kolesnichenko, K.I. Pokhodnia, and I.G. Tuluzov. Point-contact spectroscopy of the electron-phonon interaction in the layered conductor β-(bis(ethylenedithio)tetrathiofulvalene)2I3. J. Phys.: Condens. Matter, 1994, Vol.19, p.3559.

  10. M. Reiffers, Yu. G. Naidyuk, A. G. M. Jansen, P. Wyder, I. K. Yanson, D. Gignoux and D. P. Schmitt, Direct measurement of the Zeeman splitting of crystal-field levels in PrNi5 by point-contact spectroscopy, Phys. Rev. Lett. 1989, Vol.62, p.1560.

  11. I.K.Yanson, O.I.Shklyarevskii. Point-contact spectroscopy of metallic alloys and compounds (review). Sov.J.Low Temp.Phys., 1986, Vol.12, p.509.

  12. A.I.Akimenko, A.B.Verkin, I.K.Yanson. Point-contact noise spectroscopy of phonons in metals. J.Low Temp.Phys, 1984, Vol.54, p.247.

  13. I.K.Yanson. Point-contact spectroscopy of the electron-phonon interaction in pure metals (review). Sov.J.Low Temp.Phys., 1983, Vol.9, p.343.

  14. B.I. Verkin,  I.K. Yanson, I.O. Kulik, O.I. Shklyarevski, A.A. Lysykh, Yu.G. Naydyuk, Singularities in d2V/dI2 dependences of point contacts between ferromagnetic metals, Solid State Commun., 1979, Vol.30, p.215.