2006/09/30 by E. M. Motoyama, Guichuan Yu, G. Yu +5 · 5 citations
Earth and Planetary Sciences · Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Condensed matter physics #Cuprate #Electron #High-pressure geophysics and materials #Neutron scattering #Phase (matter) #Phase diagram #Phase transition #Physics #Physics of Superconductivity and Magnetism #Pseudogap #Quantum critical point #Quantum mechanics #Quantum phase transition #Scattering #Spin (aerodynamics) #Superconductivity #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1038/nature05437
published as Nature 445, 186 (2007) · 5 pages, 4 figures
openalex publication_date 2007/01/01 · arxiv created 2007/01/11 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
High-transition-temperature (high-Tc) superconductivity develops near antiferromagnetic phases, and it is possible that magnetic excitations contribute to the superconducting pairing mechanism. To assess the role of antiferromagnetism, it is essential to understand the doping and temperature dependence of the two-dimensional antiferromagnetic spin correlations. The phase diagram is asymmetric with respect to electron and hole doping, and for the comparatively less-studied electron-doped materials, the antiferromagnetic phase extends much further with doping [1, 2] and appears to overlap with the superconducting phase. The archetypical electron-doped compound Nd2-xCexCuO4±δ (NCCO) shows bulk superconductivity above x ≈ 0.13 [3, 4], while evidence for antiferromagnetic order has been found up to x ≈ 0.17 [2, 5, 6]. Here we report inelastic magnetic neutron-scattering measurements that point to the distinct possibility that genuine long-range antiferromagnetism and superconductivity do not coexist. The data reveal a magnetic quantum critical point where superconductivity first appears, consistent with an exotic quantum phase transition between the two phases [7]. We also demonstrate that the pseudogap phenomenon in the electron-doped materials, which is associated with pronounced charge anomalies [8-11], arises from a build-up of spin correlations, in agreement with recent theoretical proposals [12, 13].