Linear Scaling of the Superfluid Density with the Critical Temperature in the Layered Superconductor 2H-NbSe_2

F. O. von Rohr; J. -C. Orain; R. Khasanov; Z. Shermadini; A. Nikitin; J. Chang; A. R. Wieteska; A. N. Pasupathy; M. Z. Hasan; A. Amato; H. Luetkens; Y. J. Uemura; Z. Guguchia

doi:10.1126/sciadv.aav8465

arXiv · 1903.05292

Linear Scaling of the Superfluid Density with the Critical Temperature in the Layered Superconductor 2H-NbSe_2

F. O. von Rohr·J. -C. Orain·R. Khasanov·Z. Shermadini·A. Nikitin·J. Chang·A. R. Wieteska·A. N. Pasupathy·M. Z. Hasan·A. Amato·H. Luetkens·Y. J. Uemura·Z. Guguchia

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Abstract

We report on high-pressure (p_max = 2.1 GPa) muon spin rotation experiments probing the temperature-dependent magnetic penetration depth in the layered superconductor 2H-NbSe_2. Upon increasing the pressure, we observe a substantial increase of the superfluid density n_s, which we find to scale linearly with T_c. This linear scaling is considered a hallmark feature of unconventional superconductivity, especially in high-temperature cuprate superconductors. Our current results, along with our earlier findings on 1T'-MoTe_2 (Z. Guguchia et. al., Nature Communications 8, 1082 (2017)), demonstrate that this linear relation is also an intrinsic property of the superconductivity in transition metal dichalcogenides, whereas the ratio T_c/T_F is approximately a factor of 20 lower than the ratio observed in hole-doped cuprates. We, furthermore, find that the values of the superconducting gaps are insensitive to the suppression of the quasi-two-dimensional CDW state, indicating that the CDW ordering and the superconductivity in 2H-NbSe_2 are independent of each other.

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F. O. von Rohr, J. -C. Orain, R. Khasanov, Z. Shermadini, A. Nikitin, J. Chang, A. R. Wieteska, A. N. Pasupathy, M. Z. Hasan, A. Amato, H. Luetkens, Y. J. Uemura, Z. Guguchia. 2019-03-13. Linear Scaling of the Superfluid Density with the Critical Temperature in the Layered Superconductor 2H-NbSe_2. https://doi.org/10.1126/sciadv.aav8465

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