Publication Date:
2019
Description:
〈p〉We report on muon spin rotation experiments probing the magnetic penetration depth (〈i〉T〈/i〉) in the layered superconductors in 2H-NbSe〈sub〉2〈/sub〉 and 4H-NbSe〈sub〉2〈/sub〉. The current results, along with our earlier findings on 1T'-MoTe〈sub〉2〈/sub〉 (Guguchia 〈i〉et al.〈/i〉), demonstrate that the superfluid density scales linearly with 〈i〉T〈/i〉〈sub〉c〈/sub〉 in the three transition metal dichalcogenide superconductors. Upon increasing pressure, we observe a substantial increase of the superfluid density in 2H-NbSe〈sub〉2〈/sub〉, which we find to correlate with 〈i〉T〈/i〉〈sub〉c〈/sub〉. The correlation deviates from the abovementioned linear trend. A similar deviation from the Uemura line was also observed in previous pressure studies of optimally doped cuprates. This correlation between the superfluid density and 〈i〉T〈/i〉〈sub〉c〈/sub〉 is considered a hallmark feature of unconventional superconductivity. Here, we show that this correlation is an intrinsic property of the superconductivity in transition metal dichalcogenides, whereas the ratio 〈i〉T〈/i〉〈sub〉c〈/sub〉/〈i〉T〈/i〉〈sub〉F〈/sub〉 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 charge density wave state.〈/p〉
Electronic ISSN:
2375-2548
Topics:
Natural Sciences in General
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