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 NaFeCuAs 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 NaFeCuAs 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-T superconductivity.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5187431 | PMC |
| http://dx.doi.org/10.1038/ncomms13879 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
The First Molecular Ferroelectric Mott Insulator.
Adv Mater
January 2025
Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, P. R. China.
With the discovery of colossal magnetoresistance materials and high-temperature superconductors, Mott insulators can potentially undergo a transition from insulating state to metallic state. Here, in molecular ferroelectrics system, a Mott insulator of (CHN)VO has been first synthesized, which is a 2D organic-inorganic ferroelectric with composition of layered vanadium oxide and quinuclidine ring. Interestingly, accompanied by the ferroelectric phase transition, (CHN)VO changes sharply in conductivity.
View Article and Find Full Text PDFX-ray Nanoimaging of a Heterogeneous Structural Phase Transition in VO.
Nano Lett
January 2025
Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States.
Controlling the Mott transition through strain engineering is crucial for advancing the development of memristive and neuromorphic computing devices. Yet, Mott insulators are heterogeneous due to intrinsic phase boundaries and extrinsic defects, posing significant challenges to fully understanding the impact of microscopic distortions on the local Mott transition. Here, using a synchrotron-based scanning X-ray nanoprobe, we studied the real-space structural heterogeneity during the structural phase transition in a VO thin film.
View Article and Find Full Text PDFPseudogap in electron-doped cuprates: Strong correlation leading to band splitting.
Proc Natl Acad Sci U S A
January 2025
Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
The pseudogap phenomena have been a long-standing mystery of the cuprate high-temperature superconductors. The pseudogap in the electron-doped cuprates has been attributed to band folding due to antiferromagnetic (AFM) long-range order or short-range correlation. We performed an angle-resolved photoemission spectroscopy study of the electron-doped cuprates PrLaCeCuO showing spin-glass, disordered AFM behaviors, and superconductivity at low temperatures and, by measurements with fine momentum cuts, found that the gap opens on the unfolded Fermi surface rather than the AFM Brillouin zone boundary.
View Article and Find Full Text PDFDirect View of Gate-Tunable Miniband Dispersion in Graphene Superlattices Near the Magic Twist Angle.
ACS Nano
January 2025
Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, Aarhus C 8000, Denmark.
Superlattices from twisted graphene mono- and bilayer systems give rise to on-demand many-body states such as Mott insulators and unconventional superconductors. These phenomena are ascribed to a combination of flat bands and strong Coulomb interactions. However, a comprehensive understanding is lacking because the low-energy band structure strongly changes when an electric field is applied to vary the electron filling.
View Article and Find Full Text PDFDistinct Charge and Spin Recovery Dynamics in a Photoexcited Mott Insulator.
Phys Rev Lett
December 2024
Harish-Chandra Research Institute, A CI of Homi Bhabha National Institute, Chhatnag Road, Jhusi, Allahabad 211019, India.
Pump-probe response of the spin-orbit coupled Mott insulator Sr_{2}IrO_{4} reveals a rapid creation of low-energy optical weight and suppression of three-dimensional magnetic order on laser pumping. Postpump there is a quick reduction of the optical weight but a very slow recovery of the magnetic order-the difference is attributed to weak interlayer exchange in Sr_{2}IrO_{4} delaying the recovery of three-dimensional magnetic order. We suggest that the effect has a very different and more fundamental origin.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!