Turning charge-density waves into Cooper pairs

Chikina, Alla; Fedorov, Alexander; Bhoi, Dilip; Voroshnin, Vladimir; Haubold, Erik; Kushnirenko, Yevhen; Kim, Kee Hoon; Борисенко, С. В.

doi:10.1038/s41535-020-0225-5

“…As indicated by the last example, the combination of structural low dimensionality with superconductivity can stimulate intriguing effects, even though Little's prediction of roomtemperature superconductivity in quasi-one-dimensional materials [8,9] still remains an unobserved phenomenon at ambient pressure. Instead, a rich playing field of different ordering phenomena interacting with superconductivity has unfolded, e.g., structural transitions, charge-density and spin-density waves, and antiferromagnetism [10][11][12][13][14][15][16][17][18][19][20]. Superconducting compounds with intrinsically low-dimensional character have a special appeal to solid-state sciences, although the synthesis of large and defect-free single crystals is often challenging.…”

Section: Structurallymentioning

confidence: 99%

Structure of the superconducting high-pressure phase of Sc3CoC4

Langmann

¹

,

Vöst

²

,

Schmitz

³

et al. 2021

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We investigate pressure-induced structural changes to the Peierls-type distorted low-temperature phase of the low-dimensional Sc 3 CoC 4 as a possible origin of its pressure-enhanced superconductivity. By means of cryogenic high-pressure x-ray diffraction experiments we could reveal subtle, but significant structural differences between the low-temperature phase at ambient and elevated pressures. We could thus establish the structure of the superconducting phase of the title compound, which interestingly still shows the main features of the Peierls-type distorted low-temperature phase. This indicates that in contrast to other low-dimensional materials a suppression of periodic structural distortions is no prerequisite for superconductivity in the transition-metal carbide.

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“…( 6 ) leads to the estimation of based on the known values of the normal-state /T = 163 from Fig. 5 , the Sommerfeld coefficient = 8.56 from the specific heat measurement 23 , and = 1.4 10 m/s from the ARPES 24 . In a BCS superconductor, is usually close to the BCS coherence length 56 .…”

Section: Resultsmentioning

confidence: 99%

“…In a recent ARPES study 24 , it is found that at the normal state undergoes a Lifshitz transition with Pd intercalation, resulting in a quite different FS topology as compared with that of . In other words, the electron pockets of a dogbone shape, which are originally well separated in , have merged to form one connected, bigger Fermi surface in (see, Fig.…”

Section: Resultsmentioning

confidence: 99%

“…3 in Ref. 24 for details). At the same time, the hole pockets located at the and the points of the crystal momentum in have overall increased their areas.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, a recent ARPES study of has revealed that its underlying Fermi surface (FS) at the normal state before the CDW formation undergoes a Lifshitz transition near this particular composition, forming a van-hove singularity. As a result, topology of the underlying Fermi surface at this optimal doping regime is clearly different from that of and becomes qualiatively similar to that of 24 . In view of the fact that has exhibited nodeless muliband superconductivity, it is thus worthwhile to investigate the gap nature of with optimal .…”

Section: Introductionmentioning

confidence: 91%

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Experimental signatures of nodeless multiband superconductivity in a $$\hbox {2H-Pd}_{0.08} \hbox {TaSe}_2$$ single crystal

Kim

¹

,

Bhoi

²

,

Sur

³

et al. 2021

Sci Rep

Self Cite

1

0

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In order to understand the superconducting gap nature of a $$\hbox {2H-Pd}_{0.08} \hbox {TaSe}_2$$ 2H-Pd 0.08 TaSe 2 single crystal with $$T_{c} = 3.13 \text { K}$$ T c = 3.13 K , in-plane thermal conductivity $$\kappa $$ κ , in-plane London penetration depth $$\lambda _{\text {L}}$$ λ L , and the upper critical fields $$H_{c2}$$ H c 2 have been investigated. At zero magnetic field, it is found that no residual linear term $$\kappa _{0}/T$$ κ 0 / T exists and $$\lambda _{\text {L}}$$ λ L follows a power-law $$T^n$$ T n (T: temperature) with n = 2.66 at $$T \le \frac{1}{3}T_c$$ T ≤ 1 3 T c , supporting nodeless superconductivity. Moreover, the magnetic-field dependence of $$\kappa _{0}$$ κ 0 /T clearly shows a shoulder-like feature at a low field region. The temperature dependent $$H_{c2}$$ H c 2 curves for both in-plane and out-of-plane field directions exhibit clear upward curvatures near $$T_c$$ T c , consistent with the shape predicted by the two-band theory and the anisotropy ratio between the $$H_{c2}$$ H c 2 (T) curves exhibits strong temperature-dependence. All these results coherently suggest that $$\hbox {2H-Pd}_{0.08} \hbox {TaSe}_2$$ 2H-Pd 0.08 TaSe 2 is a nodeless, multiband superconductor.

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Coupling Between Electrons and Charge Density Wave Fluctuation and its Possible Role in Superconductivity

Lee,

Sur,

Kim

et al. 2024

Advanced Science

0

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In most charge density wave (CDW) systems of different material classes, ranging from traditional correlated systems in low‐dimension to recent topological systems with Kagome lattice, superconductivity emerges when the system is driven toward the quantum critical point (QCP) of CDW via external parameters of doping and pressure. Despite this rather universal trend, the essential hinge between CDW and superconductivity has not been established yet. Here, the evidence of coupling between electron and CDW fluctuation is reported, based on a temperature‐ and intercalation‐dependent kink in the angle‐resolved photoemission spectra of 2H‐PdxTaSe2. Kinks are observed only when the system is in the CDW phase, regardless of whether a long‐ or short‐range order is established. Notably, the coupling strength is enhanced upon long‐range CDW suppression, albeit the coupling energy scale is reduced. Interestingly, the estimation of the superconducting critical temperature by incorporating the observed coupling characteristics into McMillan's equation yields results closely resembling the known values of the superconducting dome. The results thus highlight a compelling possibility that this new coupling mediates Cooper pairs, which provides new insights into the competing relationship not only for CDW but also for other competing orders.

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Turning charge-density waves into Cooper pairs

Cited by 29 publications

References 39 publications

Structure of the superconducting high-pressure phase of Sc3CoC4

Structure of the superconducting high-pressure phase of Sc3CoC4

Experimental signatures of nodeless multiband superconductivity in a $$\hbox {2H-Pd}_{0.08} \hbox {TaSe}_2$$ single crystal

Coupling Between Electrons and Charge Density Wave Fluctuation and its Possible Role in Superconductivity

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