Observation of two-dimensional superconductivity in an ultrathin iron–arsenic superconductor

Zhang, Chi; Hu, Tao; Wang, Teng; Wu, Yufeng; Yu., A Filimonov; Chu, J. J.; Zhang, Han; Zhang, Xuefu; Xiao, H.; Peng, Wei; Di, Zengfeng; Qiao, Shuang; Mu, Gang

doi:10.1088/2053-1583/abdaba

Cited by 13 publications

(5 citation statements)

References 46 publications

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“…Interestingly, in this context, unconventional superconductivity is also discussed in the spin-triplet channel 35,36 . It is tempting to consider phase II of 174 YbRh 2 Si 2 and the putative corresponding high-field phase of YbRh 2 Si 2 to be of this kind, which would provide a compelling link to recently discovered candidate spin-triplet topological superconductors 37,38 . Of course, any model for superconductivity in YbRh 2 Si 2 (and 174 YbRh 2 Si 2 ) should also correctly capture the normal state properties.…”

Section: Resultsmentioning

confidence: 99%

Superconductivity in an extreme strange metal

et al. 2021

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Some of the highest-transition-temperature superconductors across various materials classes exhibit linear-in-temperature ‘strange metal’ or ‘Planckian’ electrical resistivities in their normal state. It is thus believed by many that this behavior holds the key to unlock the secrets of high-temperature superconductivity. However, these materials typically display complex phase diagrams governed by various competing energy scales, making an unambiguous identification of the physics at play difficult. Here we use electrical resistivity measurements into the micro-Kelvin regime to discover superconductivity condensing out of an extreme strange metal state—with linear resistivity over 3.5 orders of magnitude in temperature. We propose that the Cooper pairing is mediated by the modes associated with a recently evidenced dynamical charge localization–delocalization transition, a mechanism that may well be pertinent also in other strange metal superconductors.

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Section: Resultsmentioning

confidence: 99%

Superconductivity in an extreme strange metal

et al. 2021

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“…The ultrathin 2H-NbSe 2 device is fabricated based on our previous technique. [39] The fabrication process comprises the following three steps. (i) Fabrication of Au electrodes coated with polyvinyl alcohol (PVA) film.…”

Section: Methodsmentioning

confidence: 99%

Anisotropy of 2H-NbSe₂ in the superconducting and charge density wave states

et al. 2023

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Anisotropy is an important feature of the layered material, at which a large anisotropy is usually related to the two dimensional characteristics. We investigated the anisotropy of the layered transition metal dicalcogenide 2$H$-NbSe$_2$ at the superconducting and charge density wave (CDW) states by using magnetotransport measurements. In the superconducting state, the normalized $H_{\mathrm{c2}}^{||c}/H_p$ is independent of the thickness of 2$H$-NbSe$_2$, while $H_{\mathrm{c2}}^{||ab}/H_p$ increases significantly with decreasing the thickness, where $H_p$ is the Pauli limiting magnetic field, and $H_{\mathrm{c2}}^{||c}$ and $H_{\mathrm{c2}}^{||ab}$ are the upper critical field at $c$ and $ab$ directions, respectively. It is found that the superconducting anisotropy parameter $\gamma_{Hc2}=H_{\mathrm{c2}}^{||ab}/H_{\mathrm{c2}}^{||c}$ increases with reducing the thickness of 2$H$-NbSe$_2$. %from 4.65 in the bulk sample to 17.7 in the ultrathin sample ($5-10$ layers). In the CDW state, the angular ($\theta$) dependent of magnetoresistance $R(H,\theta)$ scales with $H(\cos^2\theta+\gamma_{CDW}^{-2}\sin^2\theta)^{1/2}$, which decreases with increasing the temperature and disappears at about 40 K. It is found that the CDW anisotropy parameter $\gamma_{CDW}$ is much larger than the effective mass anisotropy but does not change a lot for the ultrathin and bulk samples. Our results suggest the three-dimensional superconductivity and quasi-two dimensional CDW in the bulk 2$H$-NbSe$_2$.

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“…It is worth noting at this point that, in the quasi-one-dimensional case, the vortices are expected to be subject to significant confinement effect in both directions in the mixed state [9,10]. Although the upper critical field of superconductors in two-dimensional limit is well understood in terms of the 2D Ginzburg-Landau (G-L) model [1,[11][12][13][14], the behaviors in quasi-one-dimensional nanowires still need to be studied in depth and detail.…”

Section: Introductionmentioning

confidence: 99%

Size effect on the response of superconductivity in NbN nanowires to external magnetic field

Xu,

Wang,

Liu

et al. 2024

Supercond. Sci. Technol.

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Reducing the negative impact of magnetic vortex motion is a long-term challenge for superconducting applications. Here, we conduct an in-depth investigation on the response of NbN nanowires on applied magnetic fields with the transverse size down to 10 nm. It is found that the vortex-free state can sustain under field up to 9 T in the sample of this dimension, demonstrating a unique approach to reduce the negative effects of flux motion in applications. Such a conclusion is further confirmed by the vanished flux-low instability velocity. Moreover, the upper critical field of the NbN nanowires reveals clear anisotropic features, which can be interpreted based on the framework of the Ginzburg–Landau model. Our results provide important information for understanding the behavior of nanoscale superconducting materials under magnetic fields, which is significant for the application of superconducting micro/nano devices.

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Observation of two-dimensional superconductivity in an ultrathin iron–arsenic superconductor

Cited by 13 publications

References 46 publications

Superconductivity in an extreme strange metal

Superconductivity in an extreme strange metal

Anisotropy of 2H-NbSe₂ in the superconducting and charge density wave states

Size effect on the response of superconductivity in NbN nanowires to external magnetic field

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Observation of two-dimensional superconductivity in an ultrathin iron–arsenic superconductor

Cited by 13 publications

References 46 publications

Superconductivity in an extreme strange metal

Superconductivity in an extreme strange metal

Anisotropy of 2H-NbSe2 in the superconducting and charge density wave states

Size effect on the response of superconductivity in NbN nanowires to external magnetic field

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Product

Resources

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Anisotropy of 2H-NbSe₂ in the superconducting and charge density wave states