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تسجيل مستخدم جديدQuantum transport evidence of topological band structures of kagome superconductor CsV3Sb5
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We report the transport properties of kagome superconductor CsV3Sb5 single crystals at magnetic field up to 32 T. The Shubnikov de Haas (SdH) oscillations emerge at low temperature and four frequencies of $F_{alpha}=$ 27 T, F_beta = 73 T, F_epsilon = 727 T, and F_eta = 786 T with relative small cyclotron masses are observed. For F_beta and F_epsilon, the Berry phases are close to pi, providing a clear evidence of nontrivial topological band structures of CsV3Sb5. Furthermore, combined with the angular dependence of SdH oscillations and theoretical calculations based on the undistorted structure, we have demonstrated that the Fermi surface related to F_beta is quasi-two-dimensional and can be assigned to the Dirac cone along the Gamma-K direction of Brillouin zone (BZ). The F_epsilon could be related to the Fermi surface centering at the H point of BZ. The absence of F_alpha and F_eta in theoretical calculations suggests that charge density wave transition could have an important influence on the shapes of Fermi surfaces, especially near the M and L points of BZ. These results will shed light on the nature of correlated topological physics in kagome material CsV3Sb5.
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The kagome lattice of transition metal atoms provides an exciting platform to study electronic correlations in the presence of geometric frustration and nontrivial band topology, which continues to bear surprises. In this work, using spectroscopic im
aging scanning tunneling microscopy, we discover a cascade of different symmetry-broken electronic states as a function of temperature in a new kagome superconductor, CsV3Sb5. At a temperature far above the superconducting transition Tc ~ 2.5 K, we reveal a tri-directional charge order with a 2a0 period that breaks the translation symmetry of the lattice. As the system is cooled down towards Tc, we observe a prominent V-shape spectral gap opening at the Fermi level and an additional breaking of the six-fold rotation symmetry, which persists through the superconducting transition. This rotation symmetry breaking is observed as the emergence of an additional 4a0 unidirectional charge order and strongly anisotropic scattering in differential conductance maps. The latter can be directly attributed to the orbital-selective renormalization of the V kagome bands. Our experiments reveal a complex landscape of electronic states that can co-exist on a kagome lattice, and provide intriguing parallels to high-Tc superconductors and twisted bilayer graphene.
Recently, competing electronic instabilities, including superconductivity and density-wave-like order, have been discovered in vanadium-based kagome metals AV3Sb5 (A = K, Rb, Cs) with a nontrivial band topology. This finding stimulates wide interests
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Quasi-two-dimensional kagome metals AV3Sb5 (A = K, Rb, and Cs) have attracted much recent interest due to exotic quantum phenomena such as unconventional superconductivity, topological charge order and giant anomalous Hall effect. Here we report pres
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