This occurs in, for example, collisionless shock ramps in space, and in E × B discharge devices such as Hall thrusters. In the presence of a strong electric field perpendicular to the magnetic field, the electron cross-field (E × B) flow relative to the unmagnetized ions can cause the so-called electron cyclotron drift instability (ECDI) due to resonances of the ion acoustic mode and the electron cyclotron harmonics. It is shown that the MTSI mode results in strong parallel heating of = , Furthermore, the latter mode having a finite wavelength along the magnetic field is identified as the Modified Two-Stream Instability (MTSI). An intense but slowly growing mode with a distinct eigen-mode structure along the magnetic field develops at a later nonlinear stage enhancing the tendency toward long wavelength condensation. Tendency to generate long wavelength components is most clearly observed in the spectra of the electron density and the anomalous current fluctuations. At the same time, nonlinear evolution of fluctuations of the ion and electron density, as well as the anomalous electron current, shows cascade toward long wavelengths. It is found that the instability develops as a sequence of growing cyclotron harmonics demonstrating wave breaking and complex nonlinear interactions, being particularly pronounced in ion density fluctuations at short wavelengths. The emphasis is on two-dimensional effects involving the parallel dynamics along the magnetic field in a finite length plasma with dielectric walls. As shown in Fig.The Electron Cyclotron Drift Instability driven by the electron E × B drift in partially magnetized plasmas is investigated with highly resolved particle-in-cell simulations. The \(\bar\) direction coincides with the direction of Q 1 wavevector. d The original (black lines) and 2 × 2 reconstructed (blue lines) Brillouin zones. High-symmetry points and high-symmetry momentum lines are marked. c Schematic of the three-dimensional Brillouin zone and the two-dimensional Brillouin zone projected on the (001) surface in the pristine phase in a. The K, V, Sb atoms are presented as gray, purple, and blue balls, respectively. b The Tri-Hexagonal (TrH) lattice distortion caused by the 2 × 2 CDW transition 15, 25. At present, the pairing symmetry of the AV 3Sb 5 superconductors has been extensively studied and it is still being debated whether the superconductivity is unconventional 18, 19, 20, 21, 22.Ī Pristine crystal structure of KV 3Sb 5 with a V-kagome net from the top view. For example, AV 3Sb 5 family exhibit anomolous Hall effect 12, 13, although there is neither local-moment nor long-range magnetic ordering present in them 1, 12, 14 unconventional charge density wave (CDW) has been revealed in AV 3Sb 5 15, 16, 17. Such a Kagome lattice is expected to harbor topological states 3, 5, fractional charges 4, 6, density wave orders 3, 7, 8, and unconventional superconductivity 8, 9, 10, 11. The metallic Kagome lattice presents a unique electronic structure characterized by a Dirac cone at the Brillouin zone corner, von Hove singularities (VHS) at the zone boundary, and a flat band throughout the entire Brillouin zone 3, 4. 1a), the vanadium atoms form a Kagome lattice that is a two-dimensional network of corner-sharing triangles. In the crystal structure of AV 3Sb 5 (Fig. The newly discovered Kagome superconductors AV 3Sb 5 (A = K, Rb, Cs) have attracted much attention because they provide an ideal platform to investigate the interplay of topology, electron correlation effects, and superconductivity 1, 2. These results provide key insights in understanding the nature of the CDW state and its interplay with superconductivity in AV 3Sb 5 superconductors. In particular, we have observed signatures of the electron-phonon coupling in KV 3Sb 5. 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. The CDW-induced band splitting and the associated gap opening have been revealed at the boundary of the pristine and reconstructed Brillouin zones. We have observed CDW-induced Fermi surface reconstruction and the associated band folding. Here we unveil electronic nature of the CDW phase in our high-resolution angle-resolved photoemission measurements on KV 3Sb 5. High-precision electronic structure determination is essential to understand its origin. Unconventional charge density wave (CDW) has been detected in AV 3Sb 5. The Kagome superconductors AV 3Sb 5 (A = K, Rb, Cs) have received enormous attention due to their nontrivial topological electronic structure, anomalous physical properties and superconductivity.
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