Phase diagram of superconducting vortex ratchet motion in a superlattice with noncentrosymmetry

TL;DR

This paper establishes a detailed phase diagram of superconducting vortex ratchet motion in a layered superlattice superconductor, revealing how vortex dynamics respond to various external stimuli and providing insights for device applications.

Contribution

It provides the first quantitative phase diagram of vortex ratchet motion in a noncentrosymmetric superlattice superconductor using nonreciprocal magnetotransport measurements.

Findings

Demonstrated nonreciprocal magnetotransport indicating vortex ratchet motion.

Quantified the vortex ratchet motion with a giant nonreciprocal coefficient.

Proposed coexistence of pancake and Josephson vortices as the origin of ratchet motion.

Abstract

Ratchet motion of superconducting vortices, which is a directional flow of vortices in superconductors, is highly useful for exploring quantum phenomena and developing superconducting devices, such as superconducting diode and microwave antenna. However, because of the challenges in the quantitative characterization of the dynamic motion of vortices, a phase diagram of the vortex ratchet motion is still missing, especially in the superconductors with low dimensional structures. Here we establish a quantitative phase diagram of the vortex ratchet motion in a highly anisotropic superlattice superconductor, (SnS)1.17NbS2, using nonreciprocal magnetotransport. The (SnS)1.17NbS2, which possesses a layered atomic structure and noncentrosymmetry, exhibits nonreciprocal magnetotransport in a magnetic field perpendicular and parallel to the plane, which is considered a manifest of ratchet motion of superconducting vortices. We demonstrated that the ratchet motion is responsive to current excitation, magnetic field and thermal perturbation. Furthermore, we extrapolated a giant nonreciprocal coefficient ({\gamma}), which quantitatively describes the magnitude of the vortex ratchet motion, and eventually established phase diagrams of the ratchet motion of the vortices with a quantitative description. Last, we propose that the ratchet motion originates from the coexistence of pancake vortices (PVs) and Josephson vortices (JVs). The phase diagrams are desirable for controlling the vortex motion in superlattice superconductors and developing next-generation energy-efficient superconducting devices.