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A Mott insulator continuously connected to iron pnictide superconductors

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Song Yu, Yamani Zahra, Cao Chongde, Li Yu, Zhang Chenglin, Chen Justin S., Huang Qingzhen, Wu Hui, Tao Jing, Zhu Yimei, Tian Wei, Chi Songxue, Cao Huibo, Huang Yao-Bo, Dantz Marcus, Schmitt Thorsten, Yu Rong, Nevidomskyy Andriy H., Morosan Emilia, Si Qimiao, Dai Pengcheng,
Project Coupled spin, charge and orbital dynamics of low-dimensional cuprates
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Original article (peer-reviewed)

Journal Nature Communications
Volume (Issue) 7(1)
Page(s) 13879 - 13879
Title of proceedings Nature Communications
DOI 10.1038/ncomms13879

Open Access

Type of Open Access Publisher (Gold Open Access)


Iron-based superconductivity develops near an antiferromagnetic order and out of a bad-metal normal state, which has been interpreted as originating from a proximate Mott transition. Whether an actual Mott insulator can be realized in the phase diagram of the iron pnictides remains an open question. Here we use transport, transmission electron microscopy, X-ray absorption spectroscopy, resonant inelastic X-ray scattering and neutron scattering to demonstrate that NaFe1−xCuxAs near x≈0.5 exhibits real space Fe and Cu ordering, and are antiferromagnetic insulators with the insulating behaviour persisting above the Néel temperature, indicative of a Mott insulator. On decreasing x from 0.5, the antiferromagnetic-ordered moment continuously decreases, yielding to superconductivity ∼x=0.05. Our discovery of a Mott-insulating state in NaFe1−xCuxAs thus makes it the only known Fe-based material, in which superconductivity can be smoothly connected to the Mott-insulating state, highlighting the important role of electron correlations in the high-Tc superconductivity.