0000000000288039
AUTHOR
Konstantin Arutyunov
Fabrication of Quasi-One-Dimensional Superconducting Micro- and Nanostructures
Wires capable of conducting electric current are basic blocks of all electronic applications. Of particular interest for nanoelectronics are superconducting elements taking advantage of the superconductor's macroscopic quantum coherence and zero resistance. Recently there appeared indications that due to quantum fluctuations the dissipationless electric current (supercurrent) can be suppressed in ultra-narrow superconducting channels with the effective diameter below approximately 10 nm. In this Review we will describe methods of fabrication of quasi-one-dimensional superconducting micro- and nanowires suitable for electric transport measurements at cryogenic temperatures. In the first sect…
Critical temperature modification of low dimensional superconductors by spin doping
Ion implantation of Fe and Mn into Al thin films was used for effective modification of Al superconductive properties. Critical temperature of the transition to superconducting state was found to decrease gradually with implanted Fe concentration. it was found that suppression by Mn implantation much stronger compared to Fe. At low concentrations of implanted ions, suppression of the critical temperature can be described with reasonable accuracy by existing models, while at concentrations above 0.1 at.% a pronounced discrepancy between the models and experiments is observed.
Fabrication and characterization of vacuum deposited fluorescein thin films
Simple vacuum evaporation technique for deposition of dyes on various solid surfaces has been developed. The method is compatible with conventional solvent-free nanofabrication processing enabling fabrication of nanoscale optoelectronic devices. Thin films of fluorescein were deposited on glass, fluorine-tin-oxide (FTO) coated glass with and without atomically layer deposited (ALD) nanocrystalline 20 nm thick anatase TiO2 coating. Surface topology, absorption and emission spectra of the films depends on their thickness and the material of supporting substrate. On a smooth glass surface the dye initially formes islands before merging into a uniform layer after 5 to 10 monolayers. On FTO cove…
Phase Slip Phenomena in Ultra-Thin Superconducting Wires
We present results on phase-slip phenomena in a superconducting wire which can be considered as quasi-one dimensional (1D) if its characteristic transverse dimension \( \sqrt \sigma\) (√ being the cross section) is smaller than the coherence length Λ(T). The shape of the bottom part of the resistive transition R(T) of a 1D superconducting strip is described by the model of phase slips activation. If the wire is infinitely long, then there is always a finite probability that a small part of the sample is instantly driven normal.
Size-dependent enhancement of superconductivity in Al and Sn nanowires: shape-resonance effect
A shape-dependent superconducting resonance can be expected when an energy level associated with the transverse motion in a wire passes through the Fermi surface. We show that the recently observed width-dependent increase of ${T}_{c}$ in Al and Sn nanowires is a consequence of this shape-resonance effect.
High dynamic resistance elements based on a Josephson junction array
A chain of superconductor–insulator–superconductor junctions based on Al–AlOx–Al nanostructures and fabricated using conventional lift-off lithography techniques was measured at ultra-low temperatures. At zero magnetic field, the low current bias dynamic resistance can reach values of ≈1011 Ω. It was demonstrated that the system can provide a decent quality current biasing circuit, enabling the observation of Coulomb blockade and Bloch oscillations in ultra-narrow Ti nanowires associated with the quantum phase-slip effect.
Size Dependent Breakdown of Superconductivity in Ultranarrow Nanowires
Below a certain temperature Tc (typically cryogenic), some materials lose their electric resistance R entering a superconducting state. Folowing the general trend toward a large scale integration of a greater number of electronic components, it is desirable to use superconducting elements in order to minimize heat dissipation. It is expected that the basic property of a superconductor, i.e. dissipationless electric current, will be preserved at reduced scales required by modern nanoelectronics. Unfortunately, there are indications that for a certain critical size limit of the order of 10 nm, below which a "superconducting" wire is no longer a superconductor in a sense that it acquires a fin…