Phase slip lines in superconducting few-layer NbSe ₂ crystals

Abstract

We show the results of two-terminal and four-terminal transport measurements on few-layer NbSe2 devices at large current bias. In all the samples measured, transport characteristics at high bias are dominated by a series of resistance jumps due to nucleation of phase slip lines, the two dimensional analogue of phase slip centers. In point contact devices the relatively simple and homogeneous geometry enables a quantitative comparison with the model of Skocpol, Beasley and Tinkham. In extended crystals the nucleation of a single phase slip line can be induced by mechanical stress of a region whose width is comparable to the charge imbalance equilibration length.

Supercurrent diode effect and magnetochiral anisotropy in few-layer NbSe$_2$

“…Sample C. This sample has a different geometry (1 µm wide and 4 µm-long channel) and a different substrate (ceramic substrate for solid ion gating experiments) compared to all the others. It does not show a well-defined critical current: instead, it displays a series of phase slip lines, which some of the authors have studied in plain few-layer NbSe 2 crystals [23]. Owing to the peculiarities of this sample, we shall not consider it further.…”

“…1a. The exfoliated NbSe 2 crystals considered here are between 3 and 5 layers thick [23]. The flake thickness can be estimated with reasonable accuracy from the optical contrast of the crystal when stamped on standard SiO 2 /Si substrates.…”

“…Our samples are fabricated using standard exfoliation methods for TMDs [15,[22][23][24]. A scheme of the typical device is depicted in Fig.…”

Dual Fraunhofer interference and charge fluctuations in long quantum phase slip wires

“…A different approach has been taken by the two-dimensional (2D) materials community where materials engineering and encapsulation have resulted in suppressed charge disorder and significantly improved device performance [44]. Exploiting such techniques in conjunction with superconductivity in novel 2D materials [45,46] may provide an alternative route for CQPS which potentially could solve some of the challenges with spatial inhomogeneities as well. Variations in wire cross sections can easily emerge as a result of imperfect lithography defining the nanowires as well as from uncontrolled oxidation of the superconducting material or thickness variations.…”

DC Self-Field Critical Current in Superconductor/Dirac-Cone Material/Superconductor Junctions

“…It should be noted that a universal quantitatively accurate equation for critical currents at the applied magnetic field, B , is unknown to date for intrinsic superconductors [16,17,18,19,20] and for Josephson junctions [13,21,22]. However, the discussion of these important problems, as well as the discussion of interface superconductivity [23,24,25] and generic case of two-dimensional (2D) superconductivity [26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50], is beyond the scope of this paper.…”