Twofold symmetry of c-axis resistivity in topological kagome superconductor CsV3Sb5 with in-plane rotating magnetic field

Xiang, Ying; Li, Qing; Li, Yongkai; Xie, Wei; Yang, Huan; Wang, Zhiwei; Yao, Yugui; Wen, Hao

doi:10.1038/s41467-021-27084-z

Cited by 140 publications

(81 citation statements)

References 58 publications

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“…51 Similarly, NMR/NQR experiments point to the Star-of-David CDW at high temperatures, followed by an additional charge modulation below ∼ 40 K. 50 Breaking of the sixfold symmetry of the CDW state was reported experimentally for CsV 3 Sb 5 . 19,52,53 More broadly, the pressuredependent µSR data on the RbV 3 Sb 5 compound also indicates two CDW transitions. 27 Our previous low-temperature, pressure-dependent µSR data on CsV 3 Sb 5 revealed a strong change in the superfluid density within the CDW phase as pressure was varied.…”

Section: Resultsmentioning

confidence: 88%

Charge order breaks time-reversal symmetry in CsV$_3$Sb$_5$

Khasanov,

Das,

Gupta

et al. 2022

Preprint

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The recently discovered vanadium-based kagome metals AV3Sb5 (A = K, Rb, Cs) exhibit superconductivity at low-temperatures and charge density wave (CDW) order at high-temperatures. A prominent feature of the charge ordered state in this family is that it breaks time-reversal symmetry (TRSB), which is connected to the underlying topological nature of the band structure. In this work, a powerful combination of zero-field and high-field muon-spin rotation/relaxation is used to study the signatures of TRSB of the charge order in CsV3Sb5, as well as its anisotropic character. By tracking the temperature evolution of the in-plane and out-of-plane components of the muonspin polarization, an enhancement of the internal field width sensed by the muon-spin ensemble was observed below TTRSB = TCDW 95 K. Additional increase of the internal field width, accompanied by a change of the local field direction at the muon site from the ab-plane to the c-axis, was detected below T * 30 K. Remarkably, this two-step feature becomes well pronounced when a magnetic field of 8 T is applied along the crystallographic c−axis, thus indicating a field-induced enhancement of the electronic response at the CDW transition. These results point to a TRSB in CsV3Sb5 by charge order with an onset of 95 K, followed by an enhanced electronic response below 30 K. The observed two-step transition is discussed within the framework of different charge-order instabilities, which, in accordance with density functional theory calculations, are nearly degenerate in energy.

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Section: Resultsmentioning

confidence: 88%

Charge order breaks time-reversal symmetry in CsV$_3$Sb$_5$

Khasanov,

Das,

Gupta

et al. 2022

Preprint

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“…This "nematic"-like C 3 -symmetry broken phase could be stabilized on the surface, which is predicted for a real CDW ordering with k z = 0 due to the three dimensional coupling [8]. It might explain the rotational symmetry breaking due to uniaxial charge modulation observed by STM [15,16,22], two-fold c-axis magnetoresistance below T S [40,41], the enhanced m 11 − m 12 elasto-resistance coefficient above T S [55], as well as the two-fold-like amplitude of coherent phonon mode observed in the pump-probe Kerr rotation measurement [39].…”

Section: The Symmetry Of the Order Parametersmentioning

confidence: 76%

“…Furthermore, at an intermediate temperature T * about 60-70 K, an additional uniaxial 1 × 4 charge modulation was reported by STM studies [15,16,22]. Ultrafast coherent phonon spectroscopy measurements [37][38][39], muon spin relaxation measurements [34], and transport studies [40,41] all identified anomalies at around T * , suggesting a secondary instability below T S . Finally, density functional theory (DFT) phonon dispersion calculations found negative phonon frequencies at both M (1/2, 0, 0) and L(1/2, 0, 1/2) points [21], as well as at points along the U -line connecting the M and L momenta of the Brillouin zone for the high-temperature phase [11], indicating M + 1 , L − 2 , and U 1 lattice instabilities.…”

mentioning

confidence: 86%

Charge density wave order in kagome metal AV$_3$Sb$_5$ (A= Cs, Rb, K)

Wu,

Ortiz,

Tan

et al. 2022

Preprint

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We employ polarization-resolved electronic Raman spectroscopy and density functional theory to study the primary and secondary order parameters, as well as their interplay, in the charge density wave (CDW) state of the kagome metal AV3Sb5. Previous x-ray diffraction data at 15 K established that the CDW order in CsV3Sb5 comprises of a 2 × 2 × 4 structure: one layer of inverse-starof-David and three consecutive layers of star-of-David pattern. We analyze the lattice distortions based the 2 × 2 × 4 structure at 15 K, and find that U1 lattice distortion is the primary-like (leading) order parameter while M + 1 and L − 2 distortions are secondary-like order parameters for Vanadium displacements. This conclusion is confirmed by the calculation of bare susceptibility χ 0 (q) that shows a broad peak at around qz = 0.25 along the hexagonal Brillouin zone face central line (Uline). We also identify several phonon modes emerging in the CDW state, which are lattice vibration modes related to V and Sb atoms as well as alkali atoms. The detailed temperature evolution of these modes' frequencies, half-width-at-half-maximums, and integrated intensities support a phase diagram with two successive structural phase transitions in CsV3Sb5: the first one with a primarylike order parameter appearing at TS = 94 K and the second isostructural one appearing at around T * = 70 K. Furthermore, the T -dependence of the integrated intensity for these modes show two types of behavior below TS: the low-energy modes show a plateau-like behavior below T * while the high-energy modes monotonically increase below TS. These two behaviors are captured by Landau free energy model incorporating the interplay between the primary-like and the secondarylike order parameters via trilinear coupling. Especially, the sign of the trilinear term that couples order parameters with different wave-vectors determines whether the primary-like and secondarylike order parameters cooperate or compete with each other, thus determining the shape of the T -dependence of the intensities of Bragg peak in x-ray data and the amplitude modes in Raman data below TS. These results provide an accurate basis for studying the interplay between multiple CDW order parameters in kagome metal systems. I. INTRODUCTIONKagome lattice is a model system to study the electronic and magnetic properties [1,2]. The corner shared triangle network of the kagome lattice enables three sublattice interference, which give rise to a variety of exotic physics, for example, flat bands, van Hove singularities, Dirac-dispersions in its electronic structure, frustrated magnetism, to name a few. Various electronic orders such as charge/spin density wave order, charge bond order, chiral flux order, nematic order, and superconductivity are under rigorous investigations [3][4][5][6][7][8][9][10][11][12][13][14][15][16].Recently, a three-dimensional charge density wave (CDW) order, which coexists with superconductivity (SC) at low temperatures, was discovered in AV 3 Sb 5 (A= Cs, Rb, K) kagome metals [Fig. 1 ...

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“…Here, the presence of linear bands, Dirac points, and band saddle points (van Hove singularities) in the electronic structure of a nearest-neighbor kagome metal causes multiple electronic instabilities that have been studied theoretically [1][2][3][4] but did not find their way into the lab until the recent discovery of the AV 3 Sb 5 compound family with A = K, Rb, Cs [5]. Both charge-density wave (CDW) order [6][7][8][9][10][11] and superconductivity [12][13][14][15][16][17] observed experimentally in these compounds closely resemble theoretical findings for a simple kagome metal with the Fermi energy lying near the van Hove singularity at the filling level of 5 12 [18,19]. In AV 3 Sb 5 , the corresponding saddle points are clearly visible in the vanadium bands around the M point slightly below the Fermi level (Fig.…”

Section: Introductionmentioning

confidence: 99%

Role of Sb in the superconducting kagome metal CsV$_3$Sb$_5$ revealed by its anisotropic compression

Tsirlin¹,

Fertey²,

Ortiz³

et al. 2022

SciPost Phys.

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Pressure evolution of the superconducting kagome metal CsV_33Sb_55 is studied with single-crystal x-ray diffraction and density-functional band-structure calculations. A highly anisotropic compression observed up to 5 GPa is ascribed to the fast shrinkage of the Cs–Sb distances and suppression of Cs rattling motion. This prevents Sb displacements required to stabilize the three-dimensional charge-density-wave (CDW) order and elucidates the disappearance of the CDW already at 2 GPa despite only minor changes in the electronic structure of the normal state. At higher pressures, vanadium bands still change only marginally, whereas antimony bands undergo a major reconstruction caused by the gradual formation of the interlayer Sb–Sb bonds. Our results exclude pressure tuning of vanadium kagome bands as the main mechanism for the non-trivial evolution of superconductivity in real-world kagome metals. Concurrently, we establish the central role of Sb atoms in the stabilization of a three-dimensional CDW and Fermi surface reconstruction.

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Twofold symmetry of c-axis resistivity in topological kagome superconductor CsV3Sb5 with in-plane rotating magnetic field

Cited by 140 publications

References 58 publications

Charge order breaks time-reversal symmetry in CsV$_3$Sb$_5$

Charge order breaks time-reversal symmetry in CsV$_3$Sb$_5$

Charge density wave order in kagome metal AV$_3$Sb$_5$ (A= Cs, Rb, K)

Role of Sb in the superconducting kagome metal CsV$_3$Sb$_5$ revealed by its anisotropic compression

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