Topological insulator nanoribbon Josephson junctions: Evidence for size effects in transport properties

Kunakova, Gunta; Surendran, Ananthu P.; Montemurro, Domenico; Salvato, M.; Golubev, Dmitry S.; Andzane, Jana; Erts, Donāts; Lombardi, Floriana

doi:10.1063/5.0022126

Cited by 24 publications

(16 citation statements)

References 32 publications

(41 reference statements)

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“…[ 153 ] More recently, Josephson junction with Al superconducting electrodes and a Bi 2 Se 3 spacer showed a critical current minimum at zero magnetic field, possibly indicating a p ‐wave induced superconductivity. [ 154–156 ] In a recent paper on arxiv, [ 157 ] the group of David Goldhaber–Gordon reported a new technique yielding transparent interface between the 3D topological insulator (Bi 0.4 Sb 0.6 .) 2 Te 3 and the superconducting alloy PdTe, as the authors note, their results are compatible with Majorana fermions but are not an evidence for their existence.…”

Section: Current Experimental Statusmentioning

confidence: 99%

Superconducting Proximity Effect in d‐Wave Cuprate/Graphene Heterostructures

et al. 2022

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Superconducting proximity effects in graphene have received a great deal of attention for over a decade now. This has unveiled a plethora of exotic effects linked to the specificities of graphene's electronic properties. The vast majority of the related studies are based on conventional, low-temperature superconducting metals with isotropic s-wave pairing. Here recent advances made on the less studied case of unconventional high-temperature superconducting cuprates are reviewed. These are characterized by an anisotropic d-wave pairing, whose interplay with Dirac electrons yields very rich physics and novel proximity behaviors. A theoretical analysis is provided and the experiments reported so far are summarized. These unveil hints of proximity-induced unconventional pairing and demonstrate the gate-tunable, long-range propagation of high-temperature superconducting correlations in graphene. Finally, the fundamental and technological opportunities brought by the theoretical and experimental advances are discussed, together with the interest in extending similar studies to other Dirac materials.

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Section: Current Experimental Statusmentioning

confidence: 99%

Superconducting Proximity Effect in d‐Wave Cuprate/Graphene Heterostructures

et al. 2022

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“…The phase-coherence length is however expected to be comparable to the perimeter P = 430 nm of the narrow nanoribbon. The confinement in the narrow nanoribbon device is expected to result in a quantization of transverse-momenta k l [13,30,31] (schematically depicted in Fig. 1 c), right).…”

Section: Confinement In Narrow Ti Nanoribbonsmentioning

confidence: 99%

Gate-induced decoupling of surface and bulk state properties in selectively-deposited Bi$_2$Te$_3$ nanoribbons

Rosenbach,

Moors,

Jalil

et al. 2021

Preprint

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Three-dimensional topological insulators (TIs) host helical Dirac surface states at the interface with a trivial insulator. In quasi-one-dimensional TI nanoribbon structures the wave function of surface charges extends phase-coherently along the perimeter of the nanoribbon, resulting in a quantization of transverse surface modes. Furthermore, as the inherent spin-momentum locking results in a Berry phase offset of π of self-interfering charge carriers an energy gap within the surface state dispersion appears and all states become spin-degenerate. We investigate and compare the magnetic field dependent surface state dispersion in selectively deposited Bi2Te3 TI micro-and nanoribbon structures by analysing the gate voltage dependent magnetoconductance at cryogenic temperatures. Hall measurements on microribbon field effect devices show a high bulk charge carrier concentration and electrostatic simulations show an inhomogeneous gate potential profile on the perimeter of the TI ribbon. In nanoribbon devices we identify a magnetic field dependency of the surface state dispersion as it changes the occupation of transverse subbands close to the Fermi energy. We quantify the energetic spacing in between these subbands by measuring the conductance as a function of the applied gate potential and use an electrostatic model that treats the inhomogeneous gate profile and the initial charge carrier densities on the top and bottom surface. In the gate voltage dependent transconductance we find oscillations that change their relative phase by π at half-integer values of the magnetic flux quantum applied coaxial to the nanoribbon providing evidence for a magnetic flux dependent topological phase transition in narrow, selectively deposited TI nanoribbon devices.

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“…The three-dimensional topological insulator Bi 2 Se 3 has been contacted with Al leads [145] showing gate tunable supercurrent as well as Nb superconducting leads showing multiple Andreev reflections [146]. More recently, Josephson junction with Al superconducting electrodes and a Bi 2 Se 3 spacer showed a critical current minimum at zero magnetic field, possibly indicating a p-wave induced superconductivity [147,148,149]. In a recent paper on arxiv [150], the group of David Goldhaber-Gordon reported a new technique yielding transparent interface between the 3D topological insulator (Bi 0.4 Sb 0.6 ) 2 Te 3 and the superconducting alloy PdTe, as the authors note, their results are compatible with Majorana fermions but are not an evidence for their existence.…”

Section: Experiments On Topological Insulators and D-wave Superconduc...mentioning

confidence: 99%

Superconducting proximity effect in $d$-wave cuprate/ graphene heterostructures

Perconte,

Bercioux,

Dlubak

et al. 2021

Preprint

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Superconducting proximity effects in graphene have received a great deal of attention for over a decade now. This has unveiled a plethora of exotic effects linked to the specificities of graphene's electronic properties. The vast majority of the related studies are based on conventional, low-temperature superconducting metals with isotropic s-wave pairing. Here we review recent advances made on the less studied case of unconventional high-temperature superconducting cuprates. These are characterized by an anisotropic d-wave pairing, whose interplay with Dirac electrons yields very rich physics and novel proximity behaviours. We provide a theoretical analysis and summarize the experiments reported so far. These unveil hints of proximity-induced unconventional pairing and demonstrate the gate-tunable, long-range propagation of high-temperature superconducting correlations in graphene. Finally, the fundamental and technological opportunities brought by the theoretical and experimental advances are discussed, together with the interest in extending similar studies to other Dirac materials.

show abstract

Topological insulator nanoribbon Josephson junctions: Evidence for size effects in transport properties

Cited by 24 publications

References 32 publications

Superconducting Proximity Effect in d‐Wave Cuprate/Graphene Heterostructures

Superconducting Proximity Effect in d‐Wave Cuprate/Graphene Heterostructures

Gate-induced decoupling of surface and bulk state properties in selectively-deposited Bi$_2$Te$_3$ nanoribbons

Superconducting proximity effect in $d$-wave cuprate/ graphene heterostructures

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