Charge Dynamics in 122 Iron-Based Superconductors

This thesis combines highly accurate optical spectroscopy data on the recently discovered iron-based high-temperature superconductors with an incisive theoretical analysis. Three outstanding results are reported: (1) The superconductivity-induced modification of the far-infrared conductivity of an iron arsenide with minimal chemical disorder is quantitatively described by means of a strong-coupling theory for spinfluctuation mediated Cooper pairing. The formalism developed in this thesis also describes prior spectroscopic data on more disordered compounds. (2) The same materials exhibit a sharp superconductivity-induced anomaly for photon energies around 2.5 eV, two orders of magnitude larger than the superconducting energy gap. The author provides a qualitative interpretation of this unprecedented observation, which is based on the multiband nature of the superconducting state. (3) The thesis also develops a comprehensive description of a superconducting, yet optically transparent iron chalcogenide compound. The author shows that this highly unusual behavior can be explained as a result of the nanoscopic coexistence of insulating and superconducting phases, and he uses a combination of two complementary experimental methods - scanning near-field optical microscopy and low-energy muon spin rotation - to directly image the phase coexistence and quantitatively determine the phase composition. These data have important implications for the interpretation of data from other experimental probes.

List of contents

Introduction.- Iron-based superconductors.- Experimental and theoretical methods.- Results and discussion.- Summary.

Product details

• Authors: Aliaksei Charnukha
• Publisher: Springer, Berlin
• Languages: English
• Product format: Paperback / Softback
• Released: 01.01.2016
• EAN: 9783319377520
• ISBN: 978-3-31-937752-0
• No. of pages: 130
• Dimensions: 155 mm x 8 mm x 235 mm
• Weight: 230 g
• Illustrations: XI, 130 p. 43 illus., 24 illus. in color.
• Series: Springer Theses; Springer Theses
• Subjects: Natural sciences, medicine, IT, technology > Technology > Mechanical engineering, production engineering; B, Microscopy, spectroscopy, Spectroscopy and Microscopy, Optical and Electronic Materials, Nanotechnology, Physics and Astronomy, Nanoscale Science and Technology, Nanostructures, Nanoscale science, Nanophysics, Nanoscience, Electronic materials, Electronic devices & materials, Optical Materials, Spectrum analysis, spectrochemistry, mass spectrometry, Scientific equipment, experiments & techniques, Strongly Correlated Systems, Superconductivity, Superconductivity, Superconductors