Vertical Growth of Superconducting Crystalline Hollow Nanowires by He⁺ Focused Ion Beam Induced Deposition

Abstract

Novel physical properties appear when the size of a superconductor is reduced to the nanoscale, in the range of its superconducting coherence length (ξ). Such nanosuperconductors are being investigated for potential applications in nanoelectronics and quantum computing. The design of three-dimensional nanosuperconductors allows one to conceive novel schemes for such applications. Here, we report for the first time the use of a He focused-ion-beam-microscope in combination with the W(CO) precursor to grow three-dimensional superconducting hollow nanowires as small as 32 nm in diameter and with an aspect ratio (length/diameter) of as much as 200. Such extreme resolution is achieved by using a small He beam spot of 1 nm for the growth of the nanowires. As shown by transmission electron microscopy, they display grains of large size fitting with face-centered cubic WC phase. The nanowires, which are grown vertically to the substrate, are felled on the substrate by means of a nanomanipulator for their electrical characterization. They become superconducting at 6.4 K and show large critical magnetic field and critical current density resulting from their quasi-one-dimensional superconducting character. These results pave the way for future nanoelectronic devices based on three-dimensional nanosuperconductors.

Temperature-Dependent Growth Characteristics of Nb- and CoFe-Based Nanostructures by Direct-Write Using Focused Electron Beam-Induced Deposition

“…Over the last few years, this has led to the evolution of a simulation-guided 3D computer aided design (CAD) approach which was pioneered by Fowlkes and collaborators [11] and has been further developed towards a reliable instrument for 3D nano-fabrication even of complex nano-architectures, as was recently reviewed by Winkler et al [12]. For the fields of 3D nano-magnetism and nano-superconductivity, the precursors Co 2 (CO) 8 [1], Fe 2 (CO) 9 [13], HCo 3 Fe(CO) 12 [3] (FEBID), W(CO) 6 [14], and Nb(NMe 3 ) 2 (N-t-Bu) [7] (FIBID) have been used and proven to be particularly suited. With a view to the simulation-guided 3D CAD approach to nano-fabrication which uses the continuum model of FEBID/FIBID growth, a set of simulation parameters is required; see Reference [15] for a recent review.…”

High kinetic inductance microwave resonators made by He-Beam assisted deposition of tungsten nanowires

“…For a purely 2D superconductor n = 1 is expected for perpendicular magnetic fields and n = 0.5 for parallel magnetic fields. Finding an intermediate value of n points towards reduced dimensionality of superconductivity in the W nanowires [50][51][52] . From the value of H C2 and T C we extract the superconducting coherence lengths ξ and London penetration lengths λ, reported in table 1 in the article, assuming 53 µ 0 H C2 (T ) = Φ 0 /2πξ 2 (T ) and λ(0) = 1.0510 −3 ρ/T c with ρ the resistivity 54 .…”

Hollow Silica Particles: Recent Progress and Future Perspectives

“…In recent years, hollow materials have attracted significant attention from scientists working in different fields. Hollow materials with different shapes, including rods, fibers, and spherical particles, have been synthesized [1][2][3][4][5]. Of these shapes, hollow particles (spherical in shape) are the most interesting class, with applications ranging from uses in energy storage to coatings.…”