scholarly journals Unconventional superconductivity originating from disconnected Fermi surfaces in the iron-based compound

2009 ◽  
Vol 404 (5-7) ◽  
pp. 700-705 ◽  
Author(s):  
Hideo Aoki
Keyword(s):  
Unconventional Superconductivity ◽  
Fermi Surfaces ◽  
Iron Based

Unconventional Superconductivity Originating from Disconnected Fermi Surfaces in the Iron-Based Oxypnictide

2008 ◽  
Vol 77 (Suppl.C) ◽  
pp. 96-98 ◽  
Author(s):  
Kazuhiko Kuroki ◽  
Seiichiro Onari ◽  
Ryotaro Arita ◽  
Hidetomo Usui ◽  
Yukio Tanaka ◽  
...  
Keyword(s):  
Unconventional Superconductivity ◽  
Fermi Surfaces ◽  
Iron Based

scholarly journals Particle–Hole Transformation in Strongly-Doped Iron-Based Superconductors

Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 396
Author(s):  
Jose Rodriguez
Keyword(s):  
Brillouin Zone ◽  
Single Layer ◽  
Local Moment ◽  
Hole Doping ◽  
Cooper Pairs ◽  
Fermi Surfaces ◽  
Iron Based ◽  
Magnetic Resonances ◽  
Layer Iron ◽  
Electron Pocket

An exact particle–hole transformation is discovered in a local-moment model for a single layer of heavily electron-doped FeSe. The model harbors hidden magnetic order between the iron d x z and d y z orbitals at the wavenumber ( π , π ) . It potentially is tied to the magnetic resonances about the very same Néel ordering vector that have been recently discovered in intercalated FeSe. Upon electron doping, the local-moment model successfully accounts for the electron-pocket Fermi surfaces observed experimentally at the corner of the two-iron Brillouin zone in electron-doped FeSe, as well as for isotropic Cooper pairs. Application of the particle–hole transformation predicts a surface-layer iron-based superconductor at strong hole doping that exhibits high T c, and that shows hole-type Fermi-surface pockets at the center of the two-iron Brillouin zone.

scholarly journals Unconventional pairing originating from disconnected Fermi surfaces in the iron-based superconductor

2009 ◽  
Vol 11 (2) ◽  
pp. 025017 ◽  
Author(s):  
Kazuhiko Kuroki ◽  
Seiichiro Onari ◽  
Ryotaro Arita ◽  
Hidetomo Usui ◽  
Yukio Tanaka ◽  
...  
Keyword(s):  
Fermi Surfaces ◽  
Iron Based

scholarly journals Two distinct superconducting states controlled by orientations of local wrinkles in LiFeAs

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lu Cao ◽  
Wenyao Liu ◽  
Geng Li ◽  
Guangyang Dai ◽  
Qi Zheng ◽  
...  
Keyword(s):  
Local Strain ◽  
Scanning Tunneling ◽  
Strain Effect ◽  
Type I ◽  
Unconventional Superconductivity ◽  
Type Ii ◽  
Tunneling Microscopy ◽  
Iron Based Superconductors ◽  
Emergent Phenomena ◽  
Iron Based

AbstractFor iron-based superconductors, the phase diagrams under pressure or strain exhibit emergent phenomena between unconventional superconductivity and other electronic orders, varying in different systems. As a stoichiometric superconductor, LiFeAs has no structure phase transitions or entangled electronic states, which manifests an ideal platform to explore the pressure or strain effect on unconventional superconductivity. Here, we observe two types of superconducting states controlled by orientations of local wrinkles on the surface of LiFeAs. Using scanning tunneling microscopy/spectroscopy, we find type-I wrinkles enlarge the superconducting gaps and enhance the transition temperature, whereas type-II wrinkles significantly suppress the superconducting gaps. The vortices on wrinkles show a C2 symmetry, indicating the strain effects on the wrinkles. By statistics, we find that the two types of wrinkles are categorized by their orientations. Our results demonstrate that the local strain effect with different directions can tune the superconducting order parameter of LiFeAs very differently, suggesting that the band shifting induced by directional pressure may play an important role in iron-based superconductivity.

scholarly journals Pressure-induced reconstitution of Fermi surfaces and spin fluctuations in S-substituted FeSe

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
T. Kuwayama ◽  
K. Matsuura ◽  
J. Gouchi ◽  
Y. Yamakawa ◽  
Y. Mizukami ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Density Of States ◽  
Spin Fluctuations ◽  
Fermi Surfaces ◽  
Lifshitz Transition ◽  
Different Types ◽  
Iron Based ◽  
Nuclear Magnetic

AbstractFeSe is a unique high-$$T_c$$ T c iron-based superconductor in which nematicity, superconductivity, and magnetism are entangled with each other in the P-T phase diagram. We performed $$^{77}$$ 77 Se-nuclear magnetic resonance measurements under pressures of up to 3.9 GPa on 12% S-substituted FeSe, in which the complex overlap between the nematicity and magnetism are resolved. A pressure-induced Lifshitz transition was observed at 1.0 GPa as an anomaly of the density of states and as double superconducting (SC) domes accompanied by different types of antiferromagnetic (AF) fluctuations. The low-$$T_{\mathrm{c}}$$ T c SC dome below 1 GPa is accompanied by strong AF fluctuations, whereas the high-$$T_{\mathrm{c}}$$ T c SC dome develops above 1 GPa, where AF fluctuations are fairly weak. These results suggest the importance of the $$d_{xy}$$ d xy orbital and its intra-orbital coupling for the high-$$T_{\mathrm{c}}$$ T c superconductivity.

scholarly journals Possible Unconventional Superconductivity in Iron-Based Layered Compound LaFePO: Study of Heat Capacity

2008 ◽  
Vol 77 (9) ◽  
pp. 094715 ◽  
Author(s):  
Yoshimitsu Kohama ◽  
Yoichi Kamihara ◽  
Hitoshi Kawaji ◽  
Tooru Atake ◽  
Masahiro Hirano ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Layered Compound ◽  
Unconventional Superconductivity ◽  
Iron Based
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