Coulomb blockade effects in anodically oxidized titanium wires

Schöllmann, V.; Johansson, Jan; Andersson, Klas; Haviland, David B.

doi:10.1063/1.1323522

Cited by 13 publications

(8 citation statements)

References 15 publications

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“…The nanowire sheet resistivity R from 0.4 to 1.9 kΩ is still on the metallic side of the metal-to-insulator transition. Coulomb effects in titanium have been observed so far in deliberately oxidized nanowires with noticeably higher resistivity [24], [25]. However, the finite Coulomb gap above the T c requires the existence of tunnel barrier(s), presumably unintentionally formed at the overlapping regions with bismuth contacts.…”

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confidence: 98%

Coulomb Blockade and Bloch Oscillations in Superconducting Ti Nanowires

2012

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Quantum fluctuations in quasi-one-dimensional superconducting channels leading to spontaneous changes of the phase of the order parameter by 2π, alternatively called quantum phase slips (QPS), manifest themselves as the finite resistance well below the critical temperature of thin superconducting nanowires and the suppression of persistent currents in tiny superconducting nanorings. Here we report the experimental evidence that in a current-biased superconducting nanowire the same QPS process is responsible for the insulating state--the Coulomb blockade. When exposed to rf radiation, the internal Bloch oscillations can be synchronized with the external rf drive leading to formation of quantized current steps on the I-V characteristic. The effects originate from the fundamental quantum duality of a Josephson junction and a superconducting nanowire governed by QPS--the QPS junction.

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confidence: 98%

Coulomb Blockade and Bloch Oscillations in Superconducting Ti Nanowires

2012

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“…We would like to note that all our samples, including the thinnest wires with a typical sheet resistance R 200 Ω, are still comfortably on the metal side of a 'dirty' titanium. Formation of a network of weakly coupled metal grains and the corresponding Coulomb effects have been observed in deliberately oxidized titanium films with the sheet resistance R exceeding few kΩ 29 , 30 . All our samples above the critical temperature demonstrate I − V dependencies without any non-linearities, which otherwise might indicate the existence of weak links (Fig.…”

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confidence: 99%

Evidence of quantum phase slip effect in titanium nanowires

et al. 2012

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Electron transport properties of titanium nanowires were experimentally studied. Below the effective diameter 50 nm all samples demonstrated a pronounced broadening of the R(T ) dependencies, which cannot be accounted for thermal flcutuations. An extensive microscopic and elemental analysis indicates the absence of structural or/and geometrical imperfection capable to broaden the the R(T ) transition to such an extent. We associate the effect with quantum flucutuations of the order parameter.PACS numbers: 74.25.F-, 74.78.-w Since the early years of experimental studies in superconductivity it has been noticed that the supercondcunting transition R(T ) has always a finite width. Very often the broadening can be accounted for sample inhomogeneity. However, soon it became clear that, at least in low dimensional samples, the transition width remains finite even with the refined material purity and improved fabrication. The effect has been attributed to fluctuations typically more pronounced in objects with reduced dimensionality. The finite resistance R(T ) ∼ exp (−F 0 /k B T ) at a temperature T below the critical temperature T c of a quasi-one-dimensional superconducting channel with cross section σ has been explained by the thermal fluctuations of the order paprameter: the so called thermal activation of phase slips (TAPS), 1 , 2 . Here the condensation energy F 0 ∼ B 2 c ξσ of the smallest statistically independent volume ξσ, where ξ is the supercondcuting coherence length and B c is the critical magnetic field, competes with the thermal energy k B T . The effect manifests itself only sufficiently close to the critical temperature, and in extreemly homogeneous samples with micrometer-size diameter (e.g. pure whiskers) leads to the experimentally observable width of the R(T ) transition of about few mK 3 , 4 , 5 . In less homogeneous objects (e.g. lithographically fabricated nanowires) separation of the impact of the thermal fluctuations from the trivial inhomogeneity-determined R(T ) broadening is rather problematic 6 . Nevertheless with development of nanotechnology 7 it became clear that in extreemly narrow superconducting wires, with diameters ∼10 nm, the shape of the R(T ) transition by no means can be explained by sample inhomogeneity or/and thermal fluctuations 8 . The effect has been attributed to quantum fluctuations, also called -quantum phase slips (QPS) -and has been observed in a rather limited number of experiments studying the transport properties of ultra-narrow nanowires made of various superconducting materials: amorphous M oGe 9 , 10

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“…Nanocrystals of titanium monoxide are candidates for use in nanoelectronics [12] as single-electron transistors. The use of single-electron transistors based on quantum tunneling effects can significantly miniaturize computer processors.…”

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confidence: 99%

Influence of particle size, stoichiometry, and degree of long-range order on magnetic susceptibility of titanium monoxide

2016

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In situ measurements of the magnetic susceptibility of ordered and disordered titanium monoxides TiO y in the temperature range from 300 to 1200 K have revealed that it depends on the size of crystals, their stoichiometry, and long-range order parameters. Analysis of the data for both the ordered and disordered TiO y has demonstrated that the dependence of the Van Vleck paramagnetism on the nanocrystal size is inversely proportional due to the breaking of symmetry of the local environment of titanium and oxygen atoms near the surface of nanocrystals. It has been found that the Van Vleck contribution from the atomic vacancy disorder in monoxide nanocrystals of superstoichiometric composition, as well as in the crystalline stoichiometric monoxide, is proportional to the deviation of the degree of long-range order from the maximum value.

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Coulomb blockade effects in anodically oxidized titanium wires

Cited by 13 publications

References 15 publications

Coulomb Blockade and Bloch Oscillations in Superconducting Ti Nanowires

Coulomb Blockade and Bloch Oscillations in Superconducting Ti Nanowires

Evidence of quantum phase slip effect in titanium nanowires

Influence of particle size, stoichiometry, and degree of long-range order on magnetic susceptibility of titanium monoxide

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