A5102761937- Physics of Superconductivity and Magnetism
- Superconductivity in MgB2 and Alloys
- Iron-based superconductors research
- Quantum and electron transport phenomena
- Topological Materials and Phenomena
- Graphene research and applications
- Surface and Thin Film Phenomena
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Condensed Matter Physics
- Atomic and Subatomic Physics Research
- Magnesium Alloys: Properties and Applications
- Mechanical and Optical Resonators
- Semiconductor Quantum Structures and Devices
- X-ray Diffraction in Crystallography
- Quantum optics and atomic interactions
- 2D Materials and Applications
- Boron and Carbon Nanomaterials Research
- Advanced Chemical Physics Studies
- Crystal Structures and Properties
- Chemical Synthesis and Characterization
- Photonic and Optical Devices
- Superconducting Materials and Applications
Pennsylvania State University
2008-2017
Proximity-effect-induced superconductivity was studied in epitaxial topological insulator Bi2Se3 thin films grown on superconducting NbSe2 single crystals. A point contact spectroscopy (PCS) method used at low temperatures down to 40 mK. An induced gap observed the spectra, which decreased with increasing layer thickness, consistent proximity effect bulk states of by NbSe2. At very temperatures, an extra feature may correspond a second energy appeared spectrum. For 16 quintuple sample, state...
We have studied the high-field properties of carbon-doped MgB2 thin films prepared by hybrid physical–chemical vapor deposition (HPCVD). Carbon doping was accomplished adding carbon-containing gas, such as bis(methylcyclopentadienyl)magnesium and trimethylboron, into hydrogen carrier gas during deposition. In both cases, Tc drops slowly residual resistivity increases considerably with carbon doping. Both a c lattice constants increase content in films, behavior different from that bulk...
Three-dimensional topological insulators are characterized by Dirac-like conducting surface states, the existence of which has been confirmed in relatively clean metallic samples angle-resolved photoemission spectroscopy, as well anomalous Aharonov-Bohm oscillations magnetoresistance nanoribbons. However, a fundamental aspect these namely, their robustness to time-reversal-invariant disorder, remained untested. In this work, we have synthesized thin nanotubes...
Low residual resistivity in superconducting thin films is required for their applications radio frequency (RF) cavities. Here we report on clean epitaxial MgB2 fabricated by the ex situ annealing of B films, grown chemical vapour deposition, Mg vapour. The show sharp transitions at about 40 K and a high ratio 10. result indicates that precursor film contamination-free procedure are important viable fabrication process RF cavity applications.
Carbon (C)-doping has been found to increase the upper critical field HC2 in superconducting MgB2 thin-film and bulk samples. However, C effects on both lattice parameters are very different between thin films bulk, suggesting may incorporate differently two cases. This paper combines ab initio calculations parameter measurements explore connection substitutional interstitial experimental parameters.
Several theoretical analyses of the two superconducting energy gaps magnesium diboride, ∆π and ∆σ, predict substructures within each gap, rather than pure numbers.Recent experiments have revealed similar structures.We report tunneling conductance data providing additional experimental evidence for these features.The absence features in c-axis tunneling, a sharp peak subgap (associated with counterelectrode material), support conclusion that are intrinsic to MgB2.By demonstrating inadequacy...
We have grown MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> thin films using RF magnetron sputtering combined with a pocket heater. This technique relies on low-pressure environment for sputter deposition of boron and high-pressure thermal evaporation Mg. obtained superconducting substrate temperatures 480-540degC Mg furnace 730-750degC. The T xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> onset the increased from 21.6 K to 35...
Microwave resonant activation is a powerful, straightforward technique to study classical and quantum systems, experimentally realized in Josephson junction devices cooled very low temperatures. These typically consist of two single-gap superconductors separated by weak link. We report the results first experiments on hybrid thin film junctions consisting multi-gap superconductor (MgB2) (Pb or Sn). can interpret plasma frequency terms theories both for conventional junctions. Using these...
We have studied the effect of electron scattering on momentum-dependent energy gap distributions in MgB2 by measuring planar tunnel junctions made from epitaxial thin films different substrates, thicknesses, with junction interface properties, and counter-electrode materials. The phonon features tunneling spectra indicated that native oxide barrier is mainly MgO estimated thickness ranging 1.1 to 1.5 nm average height 1.7 2.6 eV. When into ab-plane occurred very clean films, both π (∼1.8...
Several theoretical analyses of the two superconducting energy gaps magnesium diboride, $Δ_π$ and $Δ_σ$, predict substructures within each gap, rather than pure numbers. Recent experiments have revealed similar structures. We report tunneling conductance data providing additional experimental evidence for these features. The absence features in c-axis tunneling, a sharp peak subgap (associated with counterelectrode material), support conclusion that are intrinsic to MgB2. By demonstrating...
Synthesizing the Natural Material NaFe3S5·2H2O In article number 2301324 by Hanqing Dai, Wei Wei, Guoqi Zhang, Ruiqian Guo, and co-workers, a systematic approach for synthesizing (NFS) with water–oxygen stability high-pressure hydrothermal method is presented. An analogy to cicada molting as strategy preparing unstable natural materials in conditions also proposed. The limitations of are broken through, which hold significant scientific implications its potential application lunar Martian...