Rosa P F S, Kang J, Luo Yongkang, Wakeham N, Bauer E D, Ronning F, Fisk Z, Fernandes R M, Thompson J D
Material Physics and Applications-Condensed Matter and Magnet Science, Los Alamos National Laboratory, Los Alamos, NM 87545.
School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455.
Proc Natl Acad Sci U S A. 2017 May 23;114(21):5384-5388. doi: 10.1073/pnas.1703016114. Epub 2017 May 9.
Applied pressure drives the heavy-fermion antiferromagnet CeRhIn toward a quantum critical point that becomes hidden by a dome of unconventional superconductivity. Magnetic fields suppress this superconducting dome, unveiling the quantum phase transition of local character. Here, we show that [Formula: see text] magnetic substitution at the Ce site in CeRhIn, either by Nd or Gd, induces a zero-field magnetic instability inside the superconducting state. This magnetic state not only should have a different ordering vector than the high-field local-moment magnetic state, but it also competes with the latter, suggesting that a spin-density-wave phase is stabilized in zero field by Nd and Gd impurities, similarly to the case of CeNdCoIn Supported by model calculations, we attribute this spin-density wave instability to a magnetic-impurity-driven condensation of the spin excitons that form inside the unconventional superconducting state.
施加压力会驱使重费米子反铁磁体CeRhIn趋向一个量子临界点，该临界点被一个非常规超导穹顶所掩盖。磁场会抑制这个超导穹顶，揭示出具有局域特征的量子相变。在此，我们表明，在CeRhIn的Ce位点进行[公式：见正文]磁性替代，无论是用Nd还是Gd，都会在超导态内部诱导出零场磁不稳定性。这种磁态不仅应该具有与高场局域磁矩磁态不同的有序矢量，而且还与后者相互竞争，这表明Nd和Gd杂质在零场中稳定了一个自旋密度波相，类似于CeNdCoIn的情况。在模型计算的支持下，我们将这种自旋密度波不稳定性归因于非常规超导态内部形成的自旋激子的磁杂质驱动凝聚。
