Clean 2D superconductivity in a bulk van der Waals superlattice

Abstract

Advances in low-dimensional superconductivity are often realized through improvements in material quality. Apart from a small group of organic materials, there is a near absence of clean-limit two-dimensional (2D) superconductors, which presents an impediment to the pursuit of numerous long-standing predictions for exotic superconductivity with fragile pairing symmetries. We developed a bulk superlattice consisting of the transition metal dichalcogenide (TMD) superconductor 2H-niobium disulfide (2H-NbS2) and a commensurate block layer that yields enhanced two-dimensionality, high electronic quality, and clean-limit inorganic 2D superconductivity. The structure of this material may naturally be extended to generate a distinct family of 2D superconductors, topological insulators, and excitonic systems based on TMDs with improved material properties.

Ising pairing in atomically thin superconductors

“…Second, nuclear magnetic resonance and thermal capacitance measurements, which are powerful in identifying the FFLO state, may not be easily applied to those atomically thin superconductors. Superlattices, where superconducting sheets are protected by insulating layers, as recently demonstrated by Devarakonda et al [72] may provide one feasible route. This A c c e p t e d M a n u s c r i p t expands the approach to encompass looking for bulk crystals with a stack of Ising superconductors separated by effectively inert layers [73].…”

“…Red: Type-II Ising superconducting materials[21,22]. Orange: "beyond" Ising-type superconductivity[50][51][52]72]. The solid symbols present the experimentally measured B c2,∥ /B BCS p ratio in each reference, which is often limited by the magnet field available.…”

Topological metals and finite-momentum superconductors

“…The interplay between spin-orbit and Zeeman splitting has interesting consequences for superconductivity, as shown in many previous works (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). Recent discovery of superconductivity in a variety of two-dimensional spin-orbit-coupled materials, including transition metal dichalcogenides (19) and strontium titanate films (20), adds additional venues for further investigation of this important problem.…”

Innovative Electron Microscopy for Multi-Layer van der Waals Heterostructures Quantum Materials Discovery

“…It is possible to form via controlled growth systems heterointerfaces in bulk materials, we present the example of our newly synthesized material Ba6Nb11S28 (see Fig. 1a) [1]. This material naturally realizes vdW coupled heterointerfaces between transition metal dichalcogenide (TMD) monolayers (hexagonal NbS2, H-NbS2) and insulating spacers Ba3NbS5 (see Fig.…”