Superconducting proximity effect in topological metals

Lee, Kyungmin; Vaezi, Abolhassan; Fischer, Mark H.; Kim, Eun-Ah

doi:10.1103/physrevb.90.214510

Cited by 12 publications

(14 citation statements)

References 32 publications

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“…4a). In thicker films, Δind gets reduced as the film thickness increases, reaching ~ 1.8 meV for the 3 QL film and ~ 1.5 meV for the 5 QL Bi2Te3 film, which is consistent with the general trend expected from theoretical calculations (28). The measured decay rate of Δind in our heterostructures is also comparable to that in Bi2Te3/NbSe2 system (8) (Fig.…”

supporting

confidence: 90%

“…We proceed to look for signatures of the induced superconductivity at the surface of Bi2Te3 and start with the 1QL Bi2Te3/Fe(Te,Se) heterostructure. This thickness should in principle maximize the magnitude of the induced superconducting gap at the TI surface, which is expected to decrease away from the interface (28). Typical dI/dV spectrum at the surface of our Bi2Te3 film reveals a clear energy gap Δind ~ 3.5 meV ( Fig.…”

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confidence: 96%

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Superconducting proximity effect in a topological insulator using Fe(Te, Se)

et al. 2018

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Interest in the superconducting proximity effect has recently been reignited by theoretical predictions that it could be used to achieve topological superconductivity. Low-Tc superconductors have predominantly been used in this effort, but small energy scales of ~1 meV have hindered the characterization of the emergent electronic phase, limiting it to extremely low temperatures. In this work, we use molecular beam epitaxy to grow topological insulator Bi2Te3 in a range of thicknesses on top of a high-Tc superconductor Fe(Te,Se). Using scanning tunneling microscopy and spectroscopy, we detect Δind as high as ~3.5 meV, which is the largest reported gap induced by proximity to an s-wave superconductor to-date. We find that Δind decays with Bi2Te3 thickness, but remains finite even after the topological surface states had been formed. Finally, by imaging the scattering and interference of surface state electrons, we provide a microscopic visualization of the fully gaped Bi2Te3 surface state due to Cooper pairing. Our results establish Fe-based high-Tc superconductors as a promising new platform for realizing high-Tc topological superconductivity.

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confidence: 90%

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confidence: 96%

Superconducting proximity effect in a topological insulator using Fe(Te, Se)

et al. 2018

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“…This is because the Fermi surface of the Bi 2 Se 3 also cut through the bulk band, and in some literature 8 it is called a topological metal. In principle the bulk bands share the tunneled Cooper pairs from the superconductor with the surface band, therefore at the same tunneling strength the pairing gap at the surface decreases compared with that without the inclusion of bulk band in a self consistent calculation 25 .…”

Section: Other Relevant Factorsmentioning

confidence: 99%

Theoretical study of large proximity-induceds-wave-like pairing from ad-wave superconductor

Chao

Lee

2016

Phys. Rev. B

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We use the proximity effect to generate effective topological superconductors by placing metals with strong spin-orbit coupling in contact with a superconductor, aiming to produce Majorana zero modes useful for topologically-protected quantum computation. In recent experiments, several quintuple layers of Bi2Se3 were epitaxially grown on the high-Tc material Bi2Sr2CaCu2O 8+δ , and conflicting experimental results were reported. We use the standard mean-field approach to study this heterostructure and find it is unlikely to have a large proximity-induced superconducting gap. Despite the seemingly correct temperature dependence, the s-wave gap claimed to be observed may not be purely superconducting in origin. Future work on the proximity-induced bulk superconducting gap and the interfacial bandstructure should shed light on this issue.

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“…2d). This would be an expected trend for a proximity-induced superconducting gap, where superconducting correlations decay away from the bulk superconductor 41 . The quick suppression of the gap away from the interface is possibly due to the relatively short-coherence length of Fe(Te,Se) 28,47 .…”

Section: Nanoscale Structural and Electronic Characterizationmentioning

confidence: 71%

Proximity-induced superconductivity in a topological crystalline insulator

Rachmilowitz

Zhao

et al. 2019

Phys. Rev. B

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Superconducting topological crystalline insulators (TCI) are predicted to host new topological phases protected by crystalline symmetries, but available materials are insufficiently suitable for surface studies. To induce superconductivity at the surface of a prototypical TCI SnTe, we use molecular beam epitaxy to grow a heterostructure of SnTe and a high-Tc superconductor Fe(Te,Se), utilizing a "buffer" layer to bridge the large lattice mismatch between SnTe and Fe(Te,Se). Using low-temperature scanning tunneling microscopy and spectroscopy, we measure a prominent spectral gap on the surface of SnTe, and demonstrate its superconducting origin by its dependence on temperature and magnetic field. Our work provides a new platform for atomic-scale investigations of emergent topological phenomena in superconducting TCIs. Introduction.

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Superconducting proximity effect in topological metals

Cited by 12 publications

References 32 publications

Superconducting proximity effect in a topological insulator using Fe(Te, Se)

Superconducting proximity effect in a topological insulator using Fe(Te, Se)

Theoretical study of large proximity-induceds-wave-like pairing from ad-wave superconductor

Proximity-induced superconductivity in a topological crystalline insulator

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