报告题目：Superconductivity of heavy fermions: The quest for coupling mechanism

报 告 人：Frank Steglich，Max Planck Institute for Chemical Physics of Solids, Dresden, Germany

报告时间：11月28日（周四）下午4：00

报告地点：理科楼郑裕彤大讲堂

报告摘要：I shall first address the early discovery of unconventional superconductivity in the heavy-fermion (HF) metal CeCu₂Si₂. Then two fundamentally different antiferromagnetic quantum-critical-point (QCP) scenarios proposed for HF metals will be briefly discussed. CeCu₂Si₂turns out to be the prototype of a conventional quantum critical material. Here, a three-dimensional spin-density-wave (SDW) QCP exists, and almost quantum-critical spin fluctuations are driving the formation of Cooper pairs.

An unconventional antiferromagnetic QCP, frequently called a 4f-orbital-selective Mott transition, at which the Kondo effect becomes destroyed, has been identified in a small number of HF systems, e.g., CeCu6-xAux [7] and YbRh2Si2. In both compounds, no superconductivity exists at T > 10 mK. However, HF superconductivity with maximum Tc ≈ 2.3 K develops in the vicinity of the pressure-induced Kondo-destroying QCP (pc ≈ 2.3 GPa) for CeRhIn5. Future research activities will have to unravel the potential differences between HFSC, driven by SDW fluctuations, and HFSC that forms in the vicinity of an orbital-selective Mott transition.