Park T, Graf M J, Boulaevskii L, Sarrao J L, Thompson J D
Condensed Matter and Thermal Physics, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
Proc Natl Acad Sci U S A. 2008 May 13;105(19):6825-8. doi: 10.1073/pnas.0801873105. Epub 2008 May 7.
Superconductivity develops from an attractive interaction between itinerant electrons that creates electron pairs, which condense into a macroscopic quantum state-the superconducting state. On the other hand, magnetic order in a metal arises from electrons localized close to the ionic core and whose interaction is mediated by itinerant electrons. The dichotomy between local moment magnetic order and superconductivity raises the question of whether these two states can coexist and involve the same electrons. Here, we show that the single 4f electron of cerium in CeRhIn(5) simultaneously produces magnetism, characteristic of localization, and superconductivity that requires itinerancy. The dual nature of the 4f-electron allows microscopic coexistence of antiferromagnetic order and superconductivity whose competition is tuned by small changes in pressure and magnetic field. Electronic duality contrasts with conventional interpretations of coexisting spin-density magnetism and superconductivity and offers a new avenue for understanding complex states in classes of materials.
超导性源于巡游电子之间的吸引相互作用，这种相互作用产生电子对，电子对凝聚成宏观量子态——超导态。另一方面，金属中的磁有序源于靠近离子芯局域化的电子，其相互作用由巡游电子介导。局域磁矩磁有序与超导性之间的二分法引发了这两种状态是否能共存且涉及相同电子的问题。在此，我们表明CeRhIn(5)中铈的单个4f电子同时产生局域化特征的磁性和需要巡游性的超导性。4f电子的双重性质允许反铁磁有序和超导性在微观层面共存，其竞争可通过压力和磁场的微小变化来调节。电子双重性与共存自旋密度磁性和超导性的传统解释形成对比，并为理解各类材料中的复杂状态提供了一条新途径。
