scholarly journals Electron-phonon coupling induced intrinsic Floquet electronic structure

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Zhigang Song ◽  
Lin-Wang Wang
Keyword(s):  
Electronic Structure ◽  
Thermal Equilibrium ◽  
Constant Voltage ◽  
Phonon Coupling ◽  
Dirac Cone ◽  
Electron Phonon Coupling ◽  
Phonon Oscillation ◽  
Floquet Theorem ◽  
Coherent Behavior ◽  
Floquet States

Abstract Floquet states are a topic of intense contemporary interest, which is often induced by coherent external oscillating perturbation (e.g., laser, or microwave) which breaks the continuous time translational symmetry of the systems. Usually, electron–phonon coupling modifies the electronic structure of a crystal as a non-coherent perturbation and seems difficult to form Floquet states. Surprisingly, we found that the thermal equilibrium electron–phonon coupling in M(MoS)3 and M(MoSe)3 (where M is a metallic element) exhibits a coherent behavior, and the electronic structure can be described by the Floquet theorem. Such a coherent Floquet state is caused by a selective giant electron–phonon coupling, with thermodynamic phonon oscillation serving as a driving force on the electronic part of the system. The quasi-1D Dirac cone at the Fermi energy has its band gap open and close regularly. Similarly, the electric current will oscillate even under a constant voltage.

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 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

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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