ﻻ يوجد ملخص باللغة العربية
Optical spectroscopy on single crystals of the new iron arsenide superconductor Ba{0.55}K{0.45}Fe2As2 shows that the infrared spectrum consists of two major components: a strong metallic Drude band and a well separated mid infrared absorption centered at 0.7 eV. It is difficult to separate the two components unambiguously but several fits of Lorentzian peaks suggest a model with a Drude peak having a plasma frequency of 1.8 to 2.1 eV and a midinfrared peak with a plasma frequency of 2.5 eV. In contrast to the cuprate superconductors the scattering rate obtained from the extended Drude model saturates at 150 meV as compared to 500 meV for a typical cuprate. Detailed analysis of the frequency dependent scattering rate shows that the charge carriers interact with broad bosonic spectrum with a peak at 25 meV and a coupling constant lambda =approx 2 at low temperature. As the temperature increases this coupling weakens to lambda=0.6 at ambient temperature. This suggests a bosonic spectrum that is similar to what is seen in the lower Tc cuprates.
To explore the origin of the unusual non-bulk superconductivity with a Tc up to 49 K reported in the rare-earth-doped CaFe2As2 , the chemical composition, magnetization, specific heat, resistivity, and annealing effect are systematically investigated
The superconducting compound, LiFeAs, is studied by scanning tunneling microscopy and spectroscopy. A gap map of the unreconstructed surface indicates a high degree of homogeneity in this system. Spectra at 2 K show two nodeless superconducting gaps
The engineering of Majorana zero modes in topological superconductors, a new paradigm for the realization of topological quantum computing and topology-based devices, has been hampered by the absence of materials with sufficiently large superconducti
We report on fabrication of devices integrating FeTe$_{0.55}$Se$_{0.45}$ with other van-der-Waals materials, measuring transport properties as well as tunneling spectra at variable magnetic fields and temperatures down to 35 mK. Transport measurement
The nature of the pairing state in iron-based superconductors is the subject of much debate. Here we argue that in one material, the stoichiometric iron pnictide KFe2As2, there is overwhelming evidence for a d-wave pairing state, characterized by sym