arXiv subjects

M. Zegrodnik

Publications and source records attributed to M. Zegrodnik.

21 records · Page 2Linked to original sources

arXiv2015

Multiband effects on the Fulde-Ferrell-Larkin-Ovchinnikov state in superconducting metallic nanofilms

In superconducting nanofilms the energy quantization induced by the confinement in the direction perpendicular to the film leads to a multiband character of the system which results in the thickness-dependent oscillations of the in-plane critical field (shape resonances). In this paper, we study the Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) phase in nanofilms and examine its interplay with the shape resonances as well as the influence of the multiband effects on its stability. We demonstrate that the range of the magnetic field for which the FFLO state is stable oscillates as a function of the film thickness with the phase shift equal to one half of the period corresponding to the critical magnetic field oscillations. Moreover, the multiband effects lead to a division of the FFLO phase stability region into subregions number of which depends on the number of bands participating in the formation of the paired state.

cond-mat.mes-hall↗

arXiv2014

Quantum size effect on the paramagnetic critical field in Pb nanofilms

The quantum size effect on the in-plane paramagnetic critical field in Pb nanofilms is investigated with the use of the spin-generalized Bogolubov-de Gennes equations. It is shown that the critical field oscillates as a function of the nanofilm thickness with the period of $\sim2$ ML (even-odd oscillations) modulated by the beating effect. This phenomena is studied in terms of the quantization of the electron energy spectra caused by the confinement of the electron motion in the direction perpendicular to the sample. The calculated values of critical fields for different nanofilm thicknesses are analyzed in the context of Clogston-Chandrasekhar limit. The influence of the thermal effect on the magnetic field induced superconductor to normal metal transition is also discussed. Furthermore, the thickness-dependence of the electron-phonon coupling and its influence on the value of the critical magnetic field are studied.

cond-mat.mes-hall↗

arXiv2013

Influence of the electron density on the thickness-dependent energy gap oscillations in superconducting metallic nanofilms

The thickness-dependent energy gap oscillations in the metallic nanofilms are investigated by the use of the self-consistent numerical solutions of the Bogoliubov-de Gennes equations. It is shown, that the oscillations are induced by the quasi-particle energy quantization triggered by the confinement of electrons in the direction perpendicular to the sample. We have analyzed, how the changes in the electron density of states ($n_e$) and the electron-phonon coupling constant ($g$) influence the amplitude of the considered oscillations. It has been found, that the increase in $n_e$ and the decrease in $g$, can lead to a significant reduction of the oscillations amplitude. As a result, for the values of the mentioned parameters corresponding to some of the realistic situations the thickness-dependent superconducting gap oscillations can be almost completely suppressed.

cond-mat.mes-hall↗