Hidden magnetism at the pseudogap critical point of a cuprate superconductor
Hidden magnetism at the pseudogap critical point of a cuprate superconductor
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DOI：
10.1038/s41567-020-0950-5
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发表时间：
2020-07-06
期刊：
影响因子：
19.6
通讯作者：
Julien, Marc-Henri
中科院分区：
文献类型：
--
作者：
Frachet, Mehdi;Vinograd, Igor;Julien, Marc-Henri
核磁共振（NMR）和超声测量表明，在铜酸盐中，自旋玻璃相一直存在，直至标志赝能隙相结束的掺杂水平。这凸显了赝能隙和莫特物理之间可能存在的联系。空穴掺杂铜酸盐超导体的赝能隙相的本质仍未被完全理解。一些实验表明，该相在一个临界空穴掺杂水平p*处结束，但更低掺杂时基态的性质仍存在争议。在此，我们利用局部核磁共振和体超声测量表明，一旦通过强磁场消除了超导的竞争效应，La(2 - x)Sr(x)CuO(4)的自旋玻璃相就会一直存在，直至与p*一致的掺杂水平。在这种材料中，反铁磁玻璃相从p = 0.02的掺杂莫特绝缘体延伸到约0.19的p*，这提供了赝能隙和莫特绝缘体物理之间的一种联系。此外，赝能隙边界与非超导基态中的磁量子相变的重合对其他实验的解释有影响，特别是对强磁场中的输运和比热测量。
NMR and ultrasound measurements show that the spin-glass phase exists in a cuprate all the way up to the doping that marks the end of the pseudogap phase. This highlights the possible connection between the pseudogap and Mott physics.The nature of the pseudogap phase of hole-doped cuprate superconductors is still not understood fully. Several experiments have suggested that this phase ends at a critical hole doping levelp*, but the nature of the ground state for lower doping is still debated. Here, we use local nuclear magnetic resonance and bulk ultrasound measurements to show that, once competing effects from superconductivity are removed by high magnetic fields, the spin-glass phase of La(2-x)Sr(x)CuO(4)survives up to a doping level consistent withp*. In this material, the antiferromagnetic-glass phase extends from the doped Mott insulator atp= 0.02 up top* approximate to 0.19, which provides a connection between the pseudogap and the physics of the Mott insulator. Furthermore, the coincidence of the pseudogap boundary with a magnetic quantum phase transition in the non-superconducting ground state has implications for the interpretation of other experiments, particularly for transport and specific-heat measurements in high magnetic fields.