Interfacial superconductivity in a bi-collinear antiferromagnetically ordered FeTe monolayer on a topological insulator

Manna, Sujit; Kamlapure, Anand; Cornils, L.; Hänke, Torben; Hedegaard, Ellen M. J.; Bremholm, Martin; Iversen, Bo B.; Hofmann, Philip; Wiebe, Jens; Wiesendanger, R.

doi:10.1038/ncomms14074

Cited by 64 publications

(68 citation statements)

References 44 publications

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“…S3) and the same gap has been detected on multiple regions of the sample separated by large distances. It is also significantly larger than that obtained on the surface of non-superconducting, antiferromagnetic parent compound FeTe monolayer grown on Bi2Te3 reported to be ~1 meV (29). The observed gap edge peaks in our dI/dV spectra are approximately symmetric with respect to the Fermi level ( Fig.…”

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confidence: 50%

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: 50%

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

et al. 2018

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“…Our results show that the spin direction at the surface is very different from the bulk. By strong spin–orbit interaction37, this will have a considerable effect on the energetics of the d -orbitals and could thereby also change the superconducting properties at the surface with respect to the bulk38. Finally, comparable SP-STM studies could offer insight into the origin of the strongly increased T C of the monolayer FeSe grown on SrTiO 3 compared with bulk FeSe789.…”

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confidence: 99%

Reorientation of the diagonal double-stripe spin structure at Fe1+yTe bulk and thin-film surfaces

Hänke¹,

Singh²,

Cornils³

et al. 2017

Nat Commun

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Establishing the relation between ubiquitous antiferromagnetism in the parent compounds of unconventional superconductors and their superconducting phase is important for understanding the complex physics in these materials. Going from bulk systems to thin films additionally affects their phase diagram. For Fe1+yTe, the parent compound of Fe1+ySe1−xTex superconductors, bulk-sensitive neutron diffraction revealed an in-plane oriented diagonal double-stripe antiferromagnetic spin structure. Here we show by spin-resolved scanning tunnelling microscopy that the spin direction at the surfaces of bulk Fe1+yTe and thin films grown on the topological insulator Bi2Te3 is canted out of the high-symmetry directions of the surface unit cell resulting in a perpendicular spin component, keeping the diagonal double-stripe order. As the magnetism of the Fe d-orbitals is intertwined with the superconducting pairing in Fe-based materials, our results imply that the superconducting properties at the surface of the related superconducting compounds might be different from the bulk.

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“…This indicates that the charge transfer in this heterostructure is robust, regardless of the Se concentration. We note that the coherence of the spectrum degrades upon Te substitution, which may be due to enhanced electron correlations [20,21] or antiferromagnetic fluctuations [22]. Strong intensity appears at the BZ center as the Se decreases.…”

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FeTe1−Se monolayer films: towards the realization of high-temperature connate topological superconductivity

et al. 2017

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† These authors contributed equally to this work [Abstract] We performed angle-resolved photoemission spectroscopy studies on a series of FeTe 1-x Se x monolayer films grown on SrTiO 3 . The superconductivity of the films is robust and rather insensitive to the variations of the band position and effective mass caused by the substitution of Se by Te. However, the band gap between the electron-and hole-like bands at the Brillouin zone center decreases towards band inversion and parity exchange, which drive the system to a nontrivial topological state predicted by theoretical calculations. Our results provide a clear experimental indication that the FeTe 1-x Se x monolayer materials are high-temperature connate topological superconductors in which band topology and superconductivity are integrated intrinsically.

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Interfacial superconductivity in a bi-collinear antiferromagnetically ordered FeTe monolayer on a topological insulator

Cited by 64 publications

References 44 publications

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

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

Reorientation of the diagonal double-stripe spin structure at Fe1+yTe bulk and thin-film surfaces

FeTe1−Se monolayer films: towards the realization of high-temperature connate topological superconductivity

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