12th CEMS Colloquium


Prof. Yuji Matsuda (Kyoto University)


16:30 - 17:30, December 4, 2013 (Wednesday)


Okochi-Hall, RIKEN


Quantum critical point hidden beneath the superconducting dome


Whether a quantum critical point (QCP) lies beneath the superconducting dome has been a long-standing issue that remains unresolved in many classes of unconventional superconductors, notably cuprates, heavy fermion compounds and most recently iron-pnictides. The existence of a QCP may offer a route to understand: the origin of their anomalous non-Fermi liquid properties, the microscopic coexistence between unconventional superconductivity and magnetic or some exotic order, and ultimately the mechanism of superconductivity itself. The isovalent substituted iron-pnictide BaFe2 (As1−x Px)2 offers a new platform for the study of quantum criticality, providing a unique opportunity to study the evolution of the electronic properties in a wide range of the phase diagram. Recent experiments in BaFe2 (As1−xPx)2 have provided the first clear and unambiguous evidence of a second order quantum phase transition lying beneath the superconducting dome. Based on these results, a new phase diagram of iron-pnictide is discussed.