Quantum interference in an interfacial superconductor

Goswami, Srijit; Mulazimoglu, Emre; Monteiro, A. M. R. V. L.; Wölbing, Roman; Koelle, D.; Kleiner, R.; Blanter, Ya. M.; Vandersypen, L. M. K.; Caviglia, Andrea D.

doi:10.1038/nnano.2016.112

Cited by 45 publications

(52 citation statements)

References 30 publications

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“…[4] This concept was first introduced in 1909 to prove the wave characteristics of photons in the double-slit experiments. [5] Now it is widely investigated in diverse research areas,s uch as nanophotonics, [6] superconductivity, [7] and quantum metrology. [8] In the studies of molecular junctions,Q Ia rises when the de Broglie waves of electrons progressing from one electrode to the other pass through different energetically accessible pathways across the molecule junction, causing interference patterns within the molecule.…”

Section: Introductionmentioning

confidence: 99%

Turning the Tap: Conformational Control of Quantum Interference to Modulate Single‐Molecule Conductance

et al. 2019

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Together with the more intuitive and commonly recognized conductance mechanisms of charge‐hopping and tunneling, quantum‐interference (QI) phenomena have been identified as important factors affecting charge transport through molecules. Consequently, establishing simple and flexible molecular‐design strategies to understand, control, and exploit QI in molecular junctions poses an exciting challenge. Here we demonstrate that destructive quantum interference (DQI) in meta‐substituted phenylene ethylene‐type oligomers (m‐OPE) can be tuned by changing the position and conformation of methoxy (OMe) substituents at the central phenylene ring. These substituents play the role of molecular‐scale taps, which can be switched on or off to control the current flow through a molecule. Our experimental results conclusively verify recently postulated magic‐ratio and orbital‐product rules, and highlight a novel chemical design strategy for tuning and gating DQI features to create single‐molecule devices with desirable electronic functions.

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Section: Introductionmentioning

confidence: 99%

Turning the Tap: Conformational Control of Quantum Interference to Modulate Single‐Molecule Conductance

et al. 2019

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“…The difference between the estimated effective area and the area of the central insulating region (5 × 5 μm 2 ) is expected and originates from flux-focusing effects due to the fact that the dimensions of the SQUID are smaller than the Pearl length (∼1 mm). 23 However, a small offset along the B -axis can be observed between the oscillations of positive and negative critical current. This asymmetry arises due to self-flux effects, which are particularly important for SQUIDs with a large kinetic inductance ( L k ).…”

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confidence: 99%

“…23 Quantum interference was observed through the integration of two such weak links in a superconducting loop, forming a superconducting quantum interference device (SQUID). 23 While the top-gating approach benefits from the ability to independently tune each of the weak links, it is rather complex due to the requirement of multiple aligned lithography steps. Moreover, it is well-established that the properties of the 2DES at the LAO/STO interface are extremely sensitive to metal and chemical adsorption 24−26 at the surface.…”

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confidence: 99%

“…In previous work it was shown that such constrictions act as a weak link between the two superconducting reservoirs, forming a Josephson junction (c-JJ type). 23 We first focus on the study and side gate modulation of transport through a single Josephson junction. In Figure 4a, the differential resistance d V /d I is plotted in color scale as a function of bias current I bias and side gates voltage V SG 1,2 , i.e., in the symmetric side gating configuration (see Supporting Information for the study as a function of the independent side gate voltages).…”

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Side Gate Tunable Josephson Junctions at the LaAlO₃/SrTiO₃ Interface

et al. 2017

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Novel physical phenomena arising at the interface of complex oxide heterostructures offer exciting opportunities for the development of future electronic devices. Using the prototypical LaAlO3/SrTiO3 interface as a model system, we employ a single-step lithographic process to realize gate-tunable Josephson junctions through a combination of lateral confinement and local side gating. The action of the side gates is found to be comparable to that of a local back gate, constituting a robust and efficient way to control the properties of the interface at the nanoscale. We demonstrate that the side gates enable reliable tuning of both the normal-state resistance and the critical (Josephson) current of the constrictions. The conductance and Josephson current show mesoscopic fluctuations as a function of the applied side gate voltage, and the analysis of their amplitude enables the extraction of the phase coherence and thermal lengths. Finally, we realize a superconducting quantum interference device in which the critical currents of each of the constriction-type Josephson junctions can be controlled independently via the side gates.

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“…Using this field effect, control of superconductivity [13][14][15][16][17], of spin-orbit coupling [17][18][19][20], and of carrier mobility [21,22] has been reported. Recent progress on local control of superconductivity [16] opened a route towards electrically controlled oxide Josephson junctions [23,24], providing new opportunities for superconducting electronic devices. Because these phenomena are related to the interfacial band structure, a fundamental understanding of the band structure is vital for the understanding of these phenomena and their exploitation in electronic devices.…”

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Gate-Tunable Band Structure of the LaAlO3−SrTiO3 Interface

et al. 2017

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The two-dimensional electron system at the interface between LaAlO 3 and SrTiO 3 has several unique properties that can be tuned by an externally applied gate voltage. In this work, we show that this gate tunability extends to the effective band structure of the system. We combine a magnetotransport study on top-gated Hall bars with self-consistent Schrödinger-Poisson calculations and observe a Lifshitz transition at a density of 2.9 × 10 13 cm −2 . Above the transition, the carrier density of one of the conducting bands decreases with increasing gate voltage. This surprising decrease is accurately reproduced in the calculations if electronic correlations are included. These results provide a clear, intuitive picture of the physics governing the electronic structure at complex-oxide interfaces. DOI: 10.1103/PhysRevLett.118.106401 The two-dimensional electron system (2DES) at the interface between the band insulators LaAlO 3 (LAO) and SrTiO 3 (STO) displays many intriguing phenomena, which may be harnessed for novel electronic devices [1][2][3][4][5]. The discovery of superconductivity [6], magnetic signatures [7][8][9][10], and their apparent coexistence [11] sparked growing interest in this material system. These properties can be tuned by varying parameters during growth [4,7], as well as by an externally applied electric field after growth [12]. Using this field effect, control of superconductivity [13][14][15][16][17], of spin-orbit coupling [17][18][19][20], and of carrier mobility [21,22] has been reported. Recent progress on local control of superconductivity [16] opened a route towards electrically controlled oxide Josephson junctions [23,24], providing new opportunities for superconducting electronic devices. Because these phenomena are related to the interfacial band structure, a fundamental understanding of the band structure is vital for the understanding of these phenomena and their exploitation in electronic devices.The interface band structure is formed by the conduction band of STO, which is bent down at the interface and crosses the Fermi level [25]. The origin of the band bending is still an open question [26][27][28]. This band bending creates a potential well, confining the carriers to a few nanometers in the out-of-plane direction [29][30][31][32]. In the well, the effective band structure is formed by the Ti t 2g orbitals. For interfaces grown along the [001] direction, the in-plane oriented d xy bands lie below the out-of-plane oriented d yz;xz bands in energy due to the confinement, as measured using x-ray absorption [33].By backgating the interface through the STO substrate, an additional conduction channel was observed to emerge above a carrier density of ð1.7 AE 0.1Þ × 10 13 cm −2 [34]. This observation was linked to tuning the Fermi level across the bottom of the d yz;xz bands, making additional electron pockets available for conduction. As a result, the Fermi surface topology changes, which is the characteristic feature of a Lifshitz transition [35].The model proposed by Joshua et...

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Quantum interference in an interfacial superconductor

Cited by 45 publications

References 30 publications

Turning the Tap: Conformational Control of Quantum Interference to Modulate Single‐Molecule Conductance

Turning the Tap: Conformational Control of Quantum Interference to Modulate Single‐Molecule Conductance

Side Gate Tunable Josephson Junctions at the LaAlO₃/SrTiO₃ Interface

Gate-Tunable Band Structure of the LaAlO3−SrTiO3 Interface

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Quantum interference in an interfacial superconductor

Cited by 45 publications

References 30 publications

Turning the Tap: Conformational Control of Quantum Interference to Modulate Single‐Molecule Conductance

Turning the Tap: Conformational Control of Quantum Interference to Modulate Single‐Molecule Conductance

Side Gate Tunable Josephson Junctions at the LaAlO3/SrTiO3 Interface

Gate-Tunable Band Structure of the LaAlO3−SrTiO3 Interface

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Product

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Side Gate Tunable Josephson Junctions at the LaAlO₃/SrTiO₃ Interface