Coexistence of two intertwined charge density waves in a kagome system

Liu, Cong; Wu, Xianxin; Liu, Hongxiong; Polley, Craig; Guo, Qinda; Wang, Yang; Han, X.; Dendzik, Maciej; Berntsen, Magnus H.; Balasubramanian, T.; Shi, Youguo; Schnyder, Andreas P.; Tjernberg, Oscar

doi:10.1103/physrevresearch.4.033072

Cited by 16 publications

(6 citation statements)

References 60 publications

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“…As demonstrated above, the slab calculation with the 1 × 1 structure shows a reasonable agreement with the experimental band structure in the Sb-terminated surface, whereas the calculation cannot reproduce the band splitting in the A-terminated surface. Since the splitting of the V-3d band is probably due to the out-of-plane unit-cell doubling and the resultant band folding along k z [48,49,68,70], the present result strongly suggests the formation of 2 × 2 × 2 CDW in the A-terminated surface and its suppression in the Sb-terminated one. While such termination/polaritydependent CDW was suggested in a previous ARPES on CsV 3 Sb 5 [48], the present result has clearly established the universality among AV 3 Sb 5 .…”

Section: Resultsmentioning

confidence: 53%

“…In the Sb-terminated surface [Figs. 2(a), 2(e), and 2(i)], the FS of all AV 3 Sb 5 consists of a circular pocket centered at the Γ point, a slightly distorted hexagon near the Brillouin-zone boundary, and a triangular pocket centered at the K point, in qualitative agree-ment with first-principles bulk-band calculations in the normal state[38,46,49,[59][60][61][62][63][64][65][66][67][68][69]. The circular pocket is attributed to the 5p z band of Sb atoms embedded in the kagome-lattice plane [Sb1 in Fig.1(a)], while the hexagonal and triangular FSs are mainly due to the V kagome-derived 3d xz /d yz and 3d xy /d x 2 −y 2 bands, respectively.…”

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confidence: 55%

“…There are two electron pockets (α and α' bands) which produce circular FSs as shown in Fig.2. The inner α band is the bulk band because it shows a clear k z dispersion (see Appendix A in the k z -dependent ARPES), while the outer α' band is possibly of surface origin[68]. One can find that, while the position of α' band is not sensitive to the A element, the bottom of α band shows a clear A-dependent energy shift; E B = 0.60 eV for KV 3 Sb 5 , 0.57 eV for RbV3 Sb 5 , and 0.53 eV for CsV 3 Sb 5 .…”

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confidence: 99%

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Surface-termination-dependent electronic states in kagome superconductors AV3Sb5 (A = K, Rb, Cs) studied by micro-ARPES

Kato¹,

Li²,

Liu³

et al. 2023

Preprint

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Recently discovered kagome superconductors AV3Sb5 (A = K, Rb, Cs) exhibit exotic bulk and surface physical properties such as charge-density wave (CDW) and chirality, whereas their origins remain unresolved. By using micro-focused angle-resolved photoemission spectroscopy, we discovered that AV3Sb5 commonly exhibits two distinct polar surfaces depending on the termination; electron-and hole-doped ones for the A-and Sb-termination, respectively. We observed that the kagome-derived band shows a clear splitting in the A-terminated surface while it is absent in the Sb-terminated counterpart, indicative of the polarity-dependent CDW at the surface. Close comparison of the band-dependent splitting reveals that the three-dimensional CDW structure of the K-terminated surface is different from that of the Rb-or Cs-terminated surface, suggesting the diversity of the CDW ground state. These results provide important insight into the origin of CDW in kagome superconductors AV3Sb5.

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Section: Resultsmentioning

confidence: 53%

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confidence: 55%

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confidence: 99%

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Surface-termination-dependent electronic states in kagome superconductors AV3Sb5 (A = K, Rb, Cs) studied by micro-ARPES

Kato¹,

Li²,

Liu³

et al. 2023

Preprint

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“…Yet, the observation of two modes modulating the in-gap intensity cannot be reconciled with amplitude oscillations of a single complex order parameter. Recent studies have shown that the out-of-plane lattice reconstruction consists of alternating SOD and iSOD distortions on adjacent layers ( 46 , 47 ) ( Fig. 1 B ).…”

Section: Discussionmentioning

confidence: 98%

Direct observation of the collective modes of the charge density wave in the kagome metal CsV ₃ Sb ₅

Azoury,

von Hoegen,

et al. 2023

Proc. Natl. Acad. Sci. U.S.A.

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A recently discovered group of kagome metals AV 3 Sb 5 (A = K, Rb, Cs) exhibit a variety of intertwined unconventional electronic phases, which emerge from a puzzling charge density wave phase. Understanding of this charge-ordered parent phase is crucial for deciphering the entire phase diagram. However, the mechanism of the charge density wave is still controversial, and its primary source of fluctuations—the collective modes—has not been experimentally observed. Here, we use ultrashort laser pulses to melt the charge order in CsV 3 Sb 5 and record the resulting dynamics using femtosecond angle-resolved photoemission. We resolve the melting time of the charge order and directly observe its amplitude mode, imposing a fundamental limit for the fastest possible lattice rearrangement time. These observations together with ab initio calculations provide clear evidence for a structural rather than electronic mechanism of the charge density wave. Our findings pave the way for a better understanding of the unconventional phases hosted on the kagome lattice.

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“…1(h), consistent with the previous ARPES reports. [32][33][34][35][36][37][38][39][40] The temperature dependence of ARPES data is shown in Fig. 2.…”

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confidence: 99%

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

Zhu

Li²,

Yu³

et al. 2023

Chinese Phys. Lett.

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Recently discovered kagome metals AV3Sb5 (A = K, Rb, and Cs) provide an ideal platform to study the correlation among nontrivial band topology, unconventional charge density wave (CDW), and superconductivity. The evolution of electronic structures associated with the change of lattice modulations is crucial for the understanding of the CDW mechanism, with the combination of ARPES measurements and DFT calculations, we investigated how band dispersions change with the increase of lattice distortions. In particular, we focus on the electronic states around ${\rm{\bar M}}$ ̅ point, where the van Hove singularities are expected to play crucial roles in the CDW transition. Previous ARPES studies reported a spectral weight splitting of the van Hove singularity around ${\rm{\bar M}}$ point, which is associated with the 3D lattice modulations. Our studies reveal that this “splitting” can be connected to the two van Hove singularities at k z =0 and k z =π/c in the normal states. When the electronic system enters into the CDW state, both van Hove singularities move down. Such novel properties are important for the understanding of the CDW transition.

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Coexistence of two intertwined charge density waves in a kagome system

Cited by 16 publications

References 60 publications

Surface-termination-dependent electronic states in kagome superconductors AV3Sb5 (A = K, Rb, Cs) studied by micro-ARPES

Surface-termination-dependent electronic states in kagome superconductors AV3Sb5 (A = K, Rb, Cs) studied by micro-ARPES

Direct observation of the collective modes of the charge density wave in the kagome metal CsV ₃ Sb ₅

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

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Coexistence of two intertwined charge density waves in a kagome system

Cited by 16 publications

References 60 publications

Surface-termination-dependent electronic states in kagome superconductors AV3Sb5 (A = K, Rb, Cs) studied by micro-ARPES

Surface-termination-dependent electronic states in kagome superconductors AV3Sb5 (A = K, Rb, Cs) studied by micro-ARPES

Direct observation of the collective modes of the charge density wave in the kagome metal CsV 3 Sb 5

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

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Direct observation of the collective modes of the charge density wave in the kagome metal CsV ₃ Sb ₅

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