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Non-Universal Superconducting Gap Structure in Iron-Pnictides Revealed by Magnetic Penetration Depth Measurements

  • Kenichiro¬†Hashimoto

Part of the Springer Theses book series (Springer Theses)

Table of contents

  1. Front Matter
    Pages i-xiii
  2. Kenichiro Hashimoto
    Pages 1-6
  3. Kenichiro Hashimoto
    Pages 19-44
  4. Kenichiro Hashimoto
    Pages 45-62
  5. Kenichiro Hashimoto
    Pages 123-125

About this book

Introduction

In this book the author presents two important findings revealed by high-precision magnetic penetration depth measurements in iron-based superconductors which exhibit high-transition temperature superconductivity up to 55 K: one is the fact that the superconducting gap structure in iron-based superconductors depends on a detailed electronic structure of individual materials, and the other is the first strong evidence for the presence of a quantum critical point (QCP) beneath the superconducting dome of iron-based superconductors.

The magnetic penetration depth is a powerful probe to elucidate the superconducting gap structure which is intimately related to the pairing mechanism of superconductivity. The author discusses the possible gap structure of individual iron-based superconductors by comparing the gap structure obtained from the penetration depth measurements with theoretical predictions, indicating that the non-universal superconducting gap structure in iron-pnictides can be interpreted in the framework of A1g symmetry. This result imposes a strong constraint on the pairing mechanism of iron-based superconductors.

The author also shows clear evidence for the quantum criticality inside the superconducting dome from the absolute zero-temperature penetration depth measurements as a function of chemical composition. A sharp peak of the penetration depth at a certain composition demonstrates pronounced quantum fluctuations associated with the QCP, which separates two distinct superconducting phases. This gives the first convincing signature of a second-order quantum phase transition deep inside the superconducting dome, which may address a key question on the general phase diagram of unconventional superconductivity in the vicinity of a QCP.

Keywords

Iron-based Superconductors Low-energy Quasiparticle Excitations Magnetic Penetration Depth Non-universal Superconducting Gap Structure Quantum Critical Point Superconducting Pairing Symmetry

Authors and affiliations

  • Kenichiro¬†Hashimoto
    • 1
  1. 1., Department of PhysicsKyoto UniversityKyotoJapan

Bibliographic information

  • DOI https://doi.org/10.1007/978-4-431-54294-0
  • Copyright Information Springer Japan 2013
  • Publisher Name Springer, Tokyo
  • eBook Packages Physics and Astronomy
  • Print ISBN 978-4-431-54293-3
  • Online ISBN 978-4-431-54294-0
  • Series Print ISSN 2190-5053
  • Series Online ISSN 2190-5061
  • Buy this book on publisher's site