Topological superconductors are a very interesting and frontier topic in condensed matter physics. Despite the tremendous efforts in exploring topological superconductivity, its presence is however still under heavy debate. The Dirac electrons have been proven to exist on the surface of a topological insulator. It remains unclear whether and how the Dirac electrons fall into Cooper pairing in an intrinsic superconductor with the topological surface states. Here we show the systematic study of scanning tunnelling microscope/spectroscopy on the possible topological superconductor SrBiSe. We first demonstrate that only the intercalated Sr atoms can induce superconductivity. Then we show the full superconducting gaps without any in-gap density of states as expected theoretically for a bulk topological superconductor. Finally, we find that the surface Dirac electrons will simultaneously condense into the superconducting state within the superconducting gap. This vividly demonstrates how the surface Dirac electrons are driven into Cooper pairs.
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http://dx.doi.org/10.1038/ncomms14466 | DOI Listing |
Ann Sci
January 2025
Niels Bohr Institute, Copenhagen University, Copenhagen, Denmark.
So-called antimatter in the form of elementary particles such as positive electrons (antielectrons alias positrons) and negative protons (antiprotons) has for long been investigated by physicists. However, atoms or molecules of this exotic kind are conspicuously absent from nature. Since antimatter is believed to be symmetric with ordinary matter, the flagrant asymmetry constitutes a problem that still worries physicists and cosmologists.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr, Tallahassee, Florida 32310, United States.
The contribution of protons in or near biradical polarizing agents in Dynamic Nuclear Polarization (DNP) has recently been under scrutiny. Results from selective deuteration and simulations have previously suggested that the role of protons in the biradical molecule depends on the strength of the electron-electron coupling. Here we use the cross effect DNP mechanism to identify and acquire H solid-state NMR spectra of the protons that contribute to propagation of the hyperpolarization, via an experimental approach dubbed Nuclear-Nuclear Double Resonance (NUDOR).
View Article and Find Full Text PDFNano Lett
January 2025
Beijing Computational Science Research Center, Beijing 100193, China.
Artificial honeycomb lattices are essential for understanding exotic quantum phenomena arising from the interplay between Dirac physics and electron correlation. This work shows that the top two moiré valence bands in rhombohedral-stacked twisted MoS bilayers (tb-MoS) form a honeycomb lattice with massless Dirac fermions. The hopping and Coulomb interaction parameters are explicitly determined based on large-scale ab initio calculations.
View Article and Find Full Text PDFInorg Chem
January 2025
Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, c/Marcel·lí Domingo 1, 43007 Tarragona, Spain.
Gas-phase synthesis and detection of boron-doped nitride clusterfullerenes and a large variety of monometallofullerenes have been achieved using a pulsed laser vaporization cluster source. Density functional theory (DFT) calculations show that the electronic structures of boron-doped endohedral metallofullerenes differ from those of the pristine all-carbon cages due to the lack of one electron upon boron substitution. For monometallofullerenes, this is likely the main reason for the somewhat different abundance distribution observed for boron-doped with respect to all-carbon cages.
View Article and Find Full Text PDFAdv Mater
January 2025
CAS Center for Excellence in Nanoscience, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, China.
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