Anisotropy of flux flow in layered superconductor 2H-NbSe2?x S x

The unusual suppression of superconducting transition temperature in double-doping 2H-NbSe2

“…However, in the 2H-Cu x NbSe 2 system, it is generally observed that the T c will drop off with an increased doping value when 'impurities' are introduced into an optimal superconductor, whereas modes in which T c declined under such instances is novel: an S-shaped superconducting phase diagram was obtained near x=0.03 with an inflection point, and there appeared to be a leveling off of the T c at about 3 K (the usual value of layered TMD) at high doping content. In contrast, there is a minor change in T c of the S substitution for Se in the 2H-NbSe 2 system [31,32].…”

“…Pristine 2H-NbSe 2 and 2H-NbS 2 are both multiband superconductors; the former has a CDW state but the latter does not [33][34][35]. On the other hand, S-doped 2H-NbSe 2 slightly affects the T c , but an unusual S-shaped superconducting phase diagram is observed when Cu ions intercalate into 2H-NbSe 2 [20,31,32]. 2H-NbSe 2 and 2H-NbS 2 thus open a door to the study of the interaction of CDW and multiband superconductivity phenomena in the bulk TMDs.…”

AC response of 2H–NbSe2single crystals with electron-irradiation-induced defects

“…These stacking faults are not directly visible by electron diffraction [10]. However, from the magnetic field dependence of the resistivity as a function of the angle between the applied field and current direction, pinning of the flux lines parallel to the layers was detected, and the cause for this strong anisotropy was also ascribed to planar stacking faults [11]. These defects provide vortex pinning at superconducting temperatures, traditionally treated under the Larkin-Ovchinnikov weak collective pinning model [12].…”