Non-universal superconducting gap structure in iron-pnictides revealed by magnetic penetration depth measurements
著者
書誌事項
Non-universal superconducting gap structure in iron-pnictides revealed by magnetic penetration depth measurements
（Springer theses : recognizing outstanding Ph. D. research）
Springer, c2013
大学図書館所蔵 全4件
注記
"Doctral thesis accepted by Kyoto University, Kyoto, Japan"
Includes bibliographical references
内容説明・目次
内容説明
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.
目次
Introduction.- Superconducting Gap Structure and Magnetic Penetration Depth.- Iron-based Superconductors.- Experimental Method.- Superconducting Gap Structure and Quantum Critical Point in BaFe2(As1-xPx)2.- Superconducting Gap Nodes in the Zone-centered Hole Bands of KFe2As2.- Nodeless vs. Nodal Order Parameter in LiFeAs and LiFeP.- Conclusions.
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