Superconducting proximity devices using low-dimensional semiconducting elements enable a ballistic regime in the proximity transport. The use of topological insulators in such devices is considered promising owing to the peculiar transport properties these materials offer, as well the hope of inducing topological superconductivity and Majorana phenomena via proximity effects. Here we demonstrate the fabrication and superconducting properties of proximity Josephson devices integrating nanocrystals single of Bi 2 Te 2.3 Se 0.7 with a thickness of a few unit cells. Single junctions display typical characteristics of planar Josephson devices; junctions integrating two nanocrystals behave as nanodimensional superconducting quantum interference devices. A peculiar temperature and magnetic field evolution of the Josephson current along with the observed excess current effect point towards the ballistic proximity regime of topological channels. This suggests the proposed devices are promising for testing topological superconducting phenomena in two-dimensions.
Josephson proximity junctions and devices employing topological insulators are promising candidates for realizing topological superconductivity and topologically protected quantum circuits. Here, the new type of oscillations of the critical Josephson current in the ballistic Nb-Bi 2 Te 2.3 Se 0.7 -Nb junctions subject to the magnetic fields is reported. The oscillations appear below ≈400 mK and have a very unusual sharp-peaked shape. Their ultra-short period ≈1 Oe, by orders of magnitude shorter than the expected periodicity due to fluxoid quantization in the device, corresponds to the extremely low energy scale ≈1 𝛍eV. It is established that the observed effect is due to the resonant transmission of Andreev quasiparticles via the peculiar energy levels forming near the S-TI interfaces.
Structural
and electronic properties of ultrathin nanocrystals
of chalcogenide Bi2(Te
x
Se1–x
)3 were studied. The
nanocrystals were formed from the parent compound Bi2Te2Se on as-grown and thermally oxidized Si(100) substrates using
Ar-assisted physical vapor deposition, resulting in well-faceted single
crystals several quintuple layers thick and a few hundreds nanometers
large. The chemical composition and structure of the nanocrystals
were analyzed by energy-dispersive X-ray spectroscopy, X-ray photoelectron
spectroscopy, electron backscattering, and X-ray diffraction. The
electron transport through nanocrystals connected to superconducting
Nb electrodes demonstrated Josephson behavior, with the predominance
of the topological channels [38Commun. Mater.20201]. The present
paper focuses on the effect of the growth conditions on the morphology,
structural, and electronic properties of nanocrystals.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.