Surface superconductivity in the type II Weyl semimetal TaIrTe4

Xing, Ying; Shao, Zhibin; Ge, Jun‐Yi; Luo, Jiawei; Wang, Jinhua; Zhu, Zengwei; Li, Jun; Wang, Yong; Zhao, Zhiying; Yan, Jiaqiang; Mandrus, David; Yan, Binghai; Liu, Xiong-Jun; Pan, Minghu; Wang, Jian

doi:10.1093/nsr/nwz204

Cited by 48 publications

(42 citation statements)

References 53 publications

(72 reference statements)

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“…1(d). R H is positive with a value in fairly good agreement with the literature [5]. Its temperature dependence suggests there is an increase in the carrier density as the temperature increases.…”

supporting

confidence: 89%

“…1(b) is metallic, with a residual resistivity ratio RRR = ρ(300 K)/ρ(0 K) = 7.4. This value is much smaller than in WTe 2 , but comparable to the results in the literature [5,11]. The resistivity is somewhat enhanced in the magnetic field, mostly at low temperature.…”

supporting

confidence: 88%

“…While ab initio calculations predicted the existence of Weyl nodes in TaIrTe 4 , surface techniques reported signatures of Fermi arcs [3], despite the challenge of Weyl cones residing above the Fermi level. A number of exotic properties have been claimed to arise in TaIrTe 4 , among them being topological edge states [4], unconventional surface superconductivity [5], bulk superconductivity under pressure [6], large Fermi arcs reaching 1/3 of the Brillouin zone dimension [3], stretchable Weyl points and line nodes [2], and a circular photogalvanic effect linked to the Berry curvature [7].…”

mentioning

confidence: 99%

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Optical conductivity of the type-II Weyl semimetal TaIrTe4

et al. 2020

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TaIrTe 4 is an example of a candidate Weyl type-II semimetal with a minimal possible number of Weyl nodes. Four nodes are reported to exist in a single plane in k space. The existence of a conical dispersion linked to Weyl nodes has yet to be shown experimentally. Here, we use optical spectroscopy as a probe of the band structure on a low-energy scale. Studying optical conductivity allows us to probe intraband and interband transitions with zero momentum. In TaIrTe 4 , we observe a narrow Drude contribution and an interband conductivity that may be consistent with a tilted linear band dispersion up to 40 meV. The interband conductivity allows us to establish the effective parameters of the conical dispersion; effective velocity v = 1.1 × 10 4 m/s and tilt γ = 0.37. The transport data, Seebeck and Hall coefficients, are qualitatively consistent with conical features in the band structure. Quantitative disagreement may be linked to the multiband nature of TaIrTe 4 .

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confidence: 89%

supporting

confidence: 88%

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confidence: 99%

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Optical conductivity of the type-II Weyl semimetal TaIrTe4

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“…For this reason, there is an ongoing effort aimed at achieving superconductivity in such materials and investigating their properties, either through the use of the proximity effect [16,18] or by other means. Successes in this area have been achieved for the type-II Weyl semimetals MoTe 2−x S x [19] and TaIrTe 4 [20], which exhibit intrinsic, exotic superconductivity. For type-I Weyl semimetals, however, such observations are still lacking.…”

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confidence: 99%

Two- and Three-Dimensional Superconducting Phases in the Weyl Semimetal TaP at Ambient Pressure

et al. 2020

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The motivation to search for signatures of superconductivity in Weyl semi-metals and other topological phases lies in their potential for hosting exotic phenomena such as nonzero-momentum pairing or the Majorana fermion, a viable candidate for the ultimate realization of a scalable quantum computer. Until now, however, all known reports of superconductivity in type-I Weyl semi-metals have arisen through surface contact with a sharp tip, focused ion-beam surface treatment or the application of high pressures. Here, we demonstrate the observation of superconductivity in single crystals, even an as-grown crystal, of the Weyl semi-metal tantalum phosphide (TaP), at ambient pressure. A superconducting transition temperature, T c , varying between 1.7 and 5.3 K, is observed in different samples, both as-grown and microscopic samples processed with focused ion beam (FIB) etching. Our data show that the superconductivity present in the as-grown crystal is inhomogeneous yet three-dimensional. For samples fabricated with FIB, we observe, in addition to the three-dimensional superconductivity, a second superconducting phase that resides on the sample surface. Through measurements of the characteristic fields as a function of temperature and angle, we are able to confirm the dimensionality of the two distinct superconducting phases.

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“…T C continuously increases with further compression and reached 2.1 K at 65.7 GPa, the maximum pressure of this study. TaIrTe 4 exhibits a strong anisotropy in transport properties and non-saturating magnetoresistance effect at ambient pressure53,[62][63][64][65] , similar to what has been seen in WTe 2 58,66-70 , thus it is of great interest to clarify the Hall coefficient (R H ) and magnetoresistance effect before and after superconducting transition because these quantities can reflect the effect of pressure on the electronic structure. Building on these ideas, we performed high-pressure Hall resistance and magnetoresistance measurements on the TaIrTe 4 sample by sweeping the magnetic field perpendicular to the ab plane up to 7 T at 10 K and different pressures, as shown inFig.4bandFig.S2in SI.…”

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confidence: 70%

Observation of superconductivity in the pressurized Weyl-semimetal candidate TaIrTe4

et al. 2019

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Here we report the observation of superconductivity in pressurized type-II Weyl semimetal (WSM) candidate TaIrTe 4 by means of complementary high-pressure transport and synchrotron X-ray diffraction measurements. We find that TaIrTe 4 shows superconductivity with transition temperature (T C ) of 0.57 K at the pressure of ~23.8 GPa. Then, the T C value increases with pressure and reaches ~2.1 K at 65.7GPa. In situ high-pressure Hall coefficient (R H ) measurements at low temperatures demonstrate that the positive R H increases with pressure until the critical pressure of the superconducting transition is reached, but starts to decrease upon further increasing pressure. Above the critical pressure, the positive magnetoresistance effect disappears simultaneously. Our high pressure X-ray diffraction measurements reveal that, at around the critical pressure the lattice of the TaIrTe 4 sample is distorted by the application of pressure and its volume is reduced by ~19.2%, the value of which is predicted to result in the change of the electronic structure significantly. We propose that the pressure-induced distortion in TaIrTe 4 is responsible for the change of topology of Fermi surface and such a change favors the emergence of superconductivity. Our results clearly demonstrate the correlation among the lattice distortion, topological physics and superconductivity in the WSM.

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Surface superconductivity in the type II Weyl semimetal TaIrTe4

Cited by 48 publications

References 53 publications

Optical conductivity of the type-II Weyl semimetal TaIrTe4

Optical conductivity of the type-II Weyl semimetal TaIrTe4

Two- and Three-Dimensional Superconducting Phases in the Weyl Semimetal TaP at Ambient Pressure

Observation of superconductivity in the pressurized Weyl-semimetal candidate TaIrTe4

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