Orbital effect on the in-plane critical field in free-standing superconducting nanofilms

Abstract

The superconductor to normal metal phase transition induced by the in-plane magnetic field is studied in free-standing Pb(111) nanofilms. In the considered structures the energy quantization induced by the confinement leads to the thickness-dependent oscillations of the critical field (the so-called 'shape resonances'). In this paper we examine the influence of the orbital effect on the in-plane critical magnetic field in nanofilms. We demonstrate that the orbital term suppresses the critical field and reduces the amplitude of the thickness-dependent critical field oscillations. Moreover, due to the orbital effect, the slope $H_{c,||}-T_c$ at $T_c(0)$ becomes finite and decreases with increasing film thickness in agreement with recent experiments. The temperature $t^{\ast }$ at which the superconductor to normal metal phase transition becomes of the first order is also analyzed.

8 pages, 7 figures

References in corpus (11)

• High-temperature interface superconductivity between metallic and insulating cuprates
• Observation of shell effects in superconducting nanoparticles of Sn
• Resonant and crossover phenomena in a multiband superconductor tuning the chemical potential near a band edge
• Two-dimensional superconducting state of monolayer Pb films grown on GaAs(110) in a strong parallel magnetic field
• Quantum size effects on the perpendicular upper critical field in ultra-thin lead films
• Magnetic-field induced quantum-size cascades in superconducting nanowires
• Superconducting transition temperature of Pb nanofilms: Impact of the thickness-dependent oscillations of the phonon mediated electron-electron coupling
• Critical temperature of MgB${}_2$ ultrathin superconducting films: BCS model calculations in tight-binding approximation
• Shape resonances and shell effects in thin-film multiband superconductors
• Quantum size effect on the paramagnetic critical field in Pb nanofilms
• Influence of the electron density on the thickness-dependent energy gap oscillations in superconducting metallic nanofilms