Physics at Virginia

"Quantum criticality and superconducting gap evolution in Fe-based superconductors"

Kyuil Cho , The Ames Laboratory and Iowa State University
[Host: Seunghun Lee]
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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