Electronic states dressed by an out-of-plane supermodulation in the quasi-two-dimensional kagome superconductor CsV3Sb5

Abstract

CsV 3 Sb 5 has attracted much recent attention as the first quasi-two-dimensional (2D) kagome superconductor. While the kagome layers are 2D in nature, increasing evidence has pointed to the importance of out-of-plane correlation in this material. However, it remains unclear whether such correlation can change the fundamental electronic structure of the quasi-2D system. Here, we reveal this missing piece of information, using angle-resolved photoemission spectroscopy, complemented by scanning tunneling microscope measurements. The three-dimensional electronic structures in the high-temperature state are revealed, which agree well with density-functional theory calculations. Electron energy bands are observed in the low-temperature state that exhibit additional periodicities along the out-of-plane momentum. These results reveal a direct response to the out-of-plane electronic supermodulation in the single-particle spectral function of CsV 3 Sb 5 , thus establishing an electronic platform to examine emergent phenomena beyond 2D limit in kagome superconductors.

A unique van Hove singularity in kagome superconductor CsV3-xTaxSb5 with enhanced superconductivity

“…2d, f, g , Supplementary Figs. S5 – S7 ), which are similar to those identified in the pristine CsV 3 Sb 5 13 , 33 . The persistence of the overall band structure and the associated orbital characters demonstrates the robustness of the kagome lattice upon Ta substitution, which also enables a quantitative examination of the changes in low energy states at different momenta.…”

“… a , b Crystal structure of CsV 3 Sb 5 ( a ) and Ta substituted CsV 3 Sb 5 ( b ). c , d Fermi surface of CsV 3 Sb 5 ( c ) and CsV 2.6 Ta 0.4 Sb 5 ( d ) measured with 56 eV photons, which probe the electronic structure in the Γ-K-M plane 33 (Supplementary Fig. S2 ).…”

Band splitting and enhanced charge density wave modulation in Mn-implanted CsV3Sb5

“…S4, † well above the CDW transition temperature. The splitting features in our samples were different from those of the band reconstruction induced by temperature evolution 38 or two-fold lattices caused by symmetry breaking 27 in the CVS system. Thirdly, the band splitting also could not be due to long-range magnetic order.…”

Electronic Instability of Kagome Metal CsV3Sb5 in the 2 × 2 × 2 Charge Density Wave State

“…As shown in Figs. 2(f)-2(j), there are also no substantial changes in band dispersions around Γ along the Γ -M as the temperature varies from 18 K to 130 K. Some reports show that the band bottom around Γ changes with temperature, [28,36] while our data suggest that such variations are minimal as indicated by the green dashed lines in Figs. 2(c)-2(e) and Figs.…”

“…For example, distinct band reconstructions in CsV3Sb5 have been reported. [28] In this Letter, we investigate band structures of kagome metal CsV3Sb5 using ARPES on the cleaved surface of a low rate of Cs coverage with a focus on the evolution of the spectral-weight splitting across the CDW tran-sition. In combination with DFT calculations, we show that there is a significant shift of spectral weight around the M point in the (001)-projected surface Brillouin zone to deeper binding energies in the CDW state.…”