The phenomenon of oxygen incorporation-induced superconductivity in iron telluride (FeTe, with antiferromagnetic (AFM) orders) is intriguing and quite different from the case of FeSe. Until now, the microscopic origin of the induced superconductivity and the role of oxygen are far from clear. Here, by combining in situ scanning tunneling microscopy/spectroscopy (STM/STS) and X-ray photoemission spectroscopy (XPS) on oxygenated FeTe, we found physically adsorbed O molecules crystallized into (2/3 × 2) structure as an oxygen overlayer at low temperature, which was vital for superconductivity. The O overlayer were not epitaxial on the FeTe lattice, which implied weak O -FeTe interaction but strong molecular interactions. The energy shift observed in the STS and XPS measurements indicated a hole doping effect from the O overlayer to the FeTe layer, leading to a superconducting gap of 4.5 meV opened across the Fermi level. Our direct microscopic probe clarified the role of oxygen on FeTe and emphasized the importance of charge transfer effect to induce superconductivity in iron-chalcogenide thin films.
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http://dx.doi.org/10.3390/ma14164584 | DOI Listing |
Commun Mater
January 2025
Physik-Institut, Universität Zürich, Zürich, Switzerland.
The discovery of unconventional superconductivity often triggers significant interest in associated electronic and structural symmetry breaking phenomena. For the infinite-layer nickelates, structural allotropes are investigated intensively. Here, using high-energy grazing-incidence x-ray diffraction, we demonstrate how in-situ temperature annealing of the infinite-layer nickelate PrNiO ( ≈ 0) induces a giant superlattice structure.
View Article and Find Full Text PDFNat Mater
January 2025
Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Chirality, a basic property of symmetry breaking, is crucial for fields such as biology and physics. Recent advances in the study of chiral systems have stimulated interest in the discovery of symmetry-breaking states that enable exotic phenomena such as spontaneous gyrotropic order and superconductivity. Here we examine the interaction between light chirality and electron spins in indium selenide and study the effect of magnetic field on emerging tunnelling photocurrents at the Van Hove singularity.
View Article and Find Full Text PDFNat Commun
January 2025
CNR Nanotec, Institute of Nanotechnology, via Monteroni, 73100, Lecce, Italy.
Macroscopic coherence in quantum fluids allows the observation of interference effects in their wavefunctions, and enables applications such as superconducting quantum interference devices based on Josephson tunneling. The Josephson effect manifests in both fermionic and bosonic systems, and has been well studied in superfluid helium and atomic Bose-Einstein condensates. In exciton-polariton condensates-that offer a path to integrated semiconductor platforms-creating weak links in ring geometries has so far remained challenging.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, United Kingdom.
Below a critical temperature [Formula: see text], superconductors transport electrical charge without dissipative energy losses. The application of a magnetic field [Formula: see text] generally acts to suppress [Formula: see text], up to some critical field strength at which [Formula: see text] 0 K. Here, we investigate magnetic field-induced superconductivity in high-quality specimens of the triplet superconductor candidate UTe[Formula: see text] in pulsed magnetic fields up to [Formula: see text] [Formula: see text] 70 T.
View Article and Find Full Text PDFSci Adv
January 2025
Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001, USA.
Superconducting spintronics explores the interplay between superconductivity and magnetism, sparking substantial interest in nonunitary superconductors as a platform for magneto-superconducting phenomena. However, identifying nonunitary superconductors remains challenging. We demonstrate that spin current driven by thermal gradients sensitively probes the nature of the condensate in nonunitary superconductors.
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