"Quantum criticality and superconducting gap evolution in Fe-based superconductors"Kyuil Cho , The Ames Laboratory and Iowa State University [Host: Seunghun Lee]
ABSTRACT:
The quantum critical point (QCP), where the transitions occur at absolute zero temperature, usually induces a new phase, such as unconventional superconductivity in organic, cuprate, heavy fermion and Fe-based superconductors. Whether the quantum critical point still exists beneath the superconducting phase is a long-standing question, but very tricky task since most of physical and magnetic properties are useless inside of superconducting phase. Here we have measured the zero-temperature penetration depth in BaFe2(As1-x,Px)2 by using tunnel diode resonator technique and identified the existence of the QCP beneath the superconducting dome [1]. In addition, the low-temperature analysis of the penetration depth measurements revealed that the superconducting gap structure shows a universal dome-like evolution as the dopant concentration increases. The details of experimental and theoretical consideration will be discussed.
[1] K. Hashimoto, Kyuil Cho, et al., Science 336, 1554 (2012). |
Condensed Matter Seminar Thursday, October 18, 2012 3:30 PM Physics Building, Room 204 Note special room. |
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