Nanoarchitecture: Toward Quantum‐Size Tuning of Superconductivity

Abstract

Quantum confinement is known to affect a nanosized superconductor through quantum‐size variations of the electronic density of states. Here, it is demonstrate that there is another quantum‐confinement mechanism overlooked in previous studies. In particular, it is found that the electron–electron attraction can be enhanced due to quantum‐confinement modifications of electronic wave functions. The superconducting correlations are strengthened by such quantum mechanical effect, which creates a subtle interplay with surface–substrate phonon modifications. The combined effect depends on nanofilm thickness and can be controlled by nanoarchitechture. The calculations are in a reasonable agreement with experiments performed on high‐quality aluminum films. These findings shed light on the long‐standing problem of the size dependence of the critical temperature in low‐dimensional superconductors.

Induced electric conductivity in organic polymers

“…Formation of thin-film lead electrodes with thicknesses from 50 nm to 200 nm was carried out by thermal evaporation in vacuum. The critical temperature of bulk lead is Т с (Pb 3D ) = 7.2 K. However, in the form of a thin film, the critical temperature of a superconductor can differ significantly from the tabulated value [ 15 – 16 ]. In our samples, the critical temperature of lead electrodes varied from 7.8 K < T c (Pb film ) < 8.2 K. Submicron PDP films were prepared by centrifuging the polymer from a solution in cyclohexanone on a solid substrate.…”

Topology and Geometry Controlled Properties of Nanoarchitectures

“…Superconducting correlations in nanofilms under the enhanced electron‐electron attraction due to quantum‐confinement modifications of electronic states in interplay with surface‐substrate phonon changes were investigated by Konstantin Arutyunov et al The combined effect was shown to be controllable by the geometry of the nanostructures. The calculations agreed with the experimental size dependence of the critical temperature in high‐quality aluminum nanofilms with the size of crystallites comparable to the film thickness.…”

Van Hove singularity driven enhancement of superconductivity in two-dimensional tungsten monofluoride (WF)

“…Superconductivity in reduced dimensional materials is a promising route for investigating the intricate interplay between electronic confinement and superconducting states * Author to whom any correspondence should be addressed. [1,2]. The transition from bulk materials, which are three-dimensional in nature, to their lower-dimensional counterparts like two-dimensional (2D) materials [3][4][5], onedimensional nanowires [6][7][8][9], and quantum dots [10,11] has a profound influence on superconducting behavior, owing to the effects of quantum confinement.…”