TY  - BOOK
AU  - Hashimoto,Kenichiro
ED  - SpringerLink (Online service)
TI  - Non-Universal Superconducting Gap Structure in Iron-Pnictides Revealed by Magnetic Penetration Depth Measurements
T2  - Springer Theses, Recognizing Outstanding Ph.D. Research,
SN  - 9784431542940
AV  - QC611.9-611.98 
U1  - 530.41 23
PY  - 2013///
CY  - Tokyo
PB  - Springer Japan, Imprint: Springer
KW  - Physics
KW  - Quantum physics
KW  - Superconductivity
KW  - Superconductors
KW  - Magnetism
KW  - Magnetic materials
KW  - Strongly Correlated Systems, Superconductivity
KW  - Quantum Physics
KW  - Magnetism, Magnetic Materials
N1  - 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
N2  - 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
UR  - http://dx.doi.org/10.1007/978-4-431-54294-0
ER  -