scholarly journals Highly-Tunable Crystal Structure and Physical Properties in FeSe-Based Superconductors

Crystals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 560 ◽  
Author(s):  
Kaiyao Zhou ◽  
Junjie Wang ◽  
Yanpeng Song ◽  
Liwei Guo ◽  
Jian-gang Guo
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Critical Role ◽  
Phonon Coupling ◽  
Inorganic Layer ◽  
Chemical Substitution ◽  
Electron Phonon Coupling ◽  
Carrier Doping ◽  
Critical Temperature Tc ◽  
Fese Superconductors

Here, crystal structure, electronic structure, chemical substitution, pressure-dependent superconductivity, and thickness-dependent properties in FeSe-based superconductors are systemically reviewed. First, the superconductivity versus chemical substitution is reviewed, where the doping at Fe or Se sites induces different effects on the superconducting critical temperature (Tc). Meanwhile, the application of high pressure is extremely effective in enhancing Tc and simultaneously induces magnetism. Second, the intercalated-FeSe superconductors exhibit higher Tc from 30 to 46 K. Such an enhancement is mainly caused by the charge transfer from the intercalated organic and inorganic layer. Finally, the highest Tc emerging in single-unit-cell FeSe on the SrTiO3 substrate is discussed, where electron-phonon coupling between FeSe and the substrate could enhance Tc to as high as 65 K or 100 K. The step-wise increment of Tc indicates that the synergic effect of carrier doping and electron-phonon coupling plays a critical role in tuning the electronic structure and superconductivity in FeSe-based superconductors.

scholarly journals Electron-Phonon Coupling Parameter of Ferromagnetic Metal Fe and Co

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2755
Author(s):  
Kyuhwe Kang ◽  
Gyung-Min Choi
Keyword(s):  
Coupling Parameter ◽  
Critical Role ◽  
Circuit Modeling ◽  
Metallic Materials ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Complicated Process ◽  
G Value ◽  
Non Equilibrium

The electron-phonon coupling (g) parameter plays a critical role in the ultrafast transport of heat, charge, and spin in metallic materials. However, the exact determination of the g parameter is challenging because of the complicated process during the non-equilibrium state. In this study, we investigate the g parameters of ferromagnetic 3d transition metal (FM) layers, Fe and Co, using time-domain thermoreflectance. We measure a transient increase in temperature of Au in an FM/Au bilayer; the Au layer efficiently detects the strong heat flow during the non-equilibrium between electrons and phonons in FM. The g parameter of the FM is determined by analyzing the temperature dynamics using thermal circuit modeling. The determined g values are 8.8–9.4 × 1017 W m−3 K−1 for Fe and 9.6–12.2 × 1017 W m−3 K−1 for Co. Our results demonstrate that all 3d transition FMs have a similar g value, in the order of 1018 W m−3 K−1.

scholarly journals Electronic structure and electron-phonon coupling of doped graphene layers inKC8

2009 ◽  
Vol 79 (20) ◽  
Author(s):  
A. Grüneis ◽  
C. Attaccalite ◽  
A. Rubio ◽  
D. V. Vyalikh ◽  
S. L. Molodtsov ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Phonon Coupling ◽  
Graphene Layers ◽  
Electron Phonon Coupling ◽  
Doped Graphene

STRUCTURE EFFECT ON THE AlB2-LIKE SUPERCONDUCTOR CaAlSi

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3330-3333
Author(s):  
R. MA ◽  
M. LIU ◽  
G. Q. HUANG
Keyword(s):  
Crystal Structure ◽  
First Principles ◽  
Structure Effect ◽  
First Principles Calculations ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Theory And Experiment

In this paper, using the first-principles calculations, we study the crystal structure effect on the superconductivity in CaAlSi . It is proposed that an AF-like superstructure model for Al (or Si ) atoms arranged along the c direction may mediate the inconsistency of the electron-phonon coupling estimated from theory and experiment, and explain the anomalous superconductivity in CaAlSi .

scholarly journals Electronic structure and weak electron-phonon coupling inTaB2

2001 ◽  
Vol 64 (14) ◽  
Author(s):  
H. Rosner ◽  
W. E. Pickett ◽  
S.-L. Drechsler ◽  
A. Handstein ◽  
G. Behr ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Weak Electron

scholarly journals Electronic nature of charge density wave and electron-phonon coupling in kagome superconductor KV3Sb5

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Hailan Luo ◽  
Qiang Gao ◽  
Hongxiong Liu ◽  
Yuhao Gu ◽  
Dingsong Wu ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Fermi Surface ◽  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Phonon Coupling ◽  
Electronic Nature ◽  
Electron Phonon Coupling ◽  
Gap Opening ◽  
Fermi Surface Reconstruction

AbstractThe Kagome superconductors AV3Sb5 (A = K, Rb, Cs) have received enormous attention due to their nontrivial topological electronic structure, anomalous physical properties and superconductivity. Unconventional charge density wave (CDW) has been detected in AV3Sb5. High-precision electronic structure determination is essential to understand its origin. Here we unveil electronic nature of the CDW phase in our high-resolution angle-resolved photoemission measurements on KV3Sb5. We have observed CDW-induced Fermi surface reconstruction and the associated band folding. The CDW-induced band splitting and the associated gap opening have been revealed at the boundary of the pristine and reconstructed Brillouin zones. The Fermi surface- and momentum-dependent CDW gap is measured and the strongly anisotropic CDW gap is observed for all the V-derived Fermi surface. In particular, we have observed signatures of the electron-phonon coupling in KV3Sb5. These results provide key insights in understanding the nature of the CDW state and its interplay with superconductivity in AV3Sb5 superconductors.

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