Nematic Ising superconductivity with hidden magnetism in few-layer 6R-TaS2

TL;DR

This paper reports the discovery of nematic Ising superconductivity with hidden magnetism in few-layer 6R-TaS2, revealing complex intertwined quantum phenomena driven by interlayer coupling in van der Waals heterostructures.

Contribution

It demonstrates the emergence of a novel phase with hidden magnetism and nematicity coexisting with Ising superconductivity in 6R-TaS2, a natural van der Waals heterostructure.

Findings

Observation of a phase with giant anomalous Hall effect and thermal hysteresis below T* ~30 K

Coexistence of nematicity, Kondo screening, and Ising superconductivity at low temperatures

Evidence of hidden magnetism within a superconductor in 6R-TaS2

Abstract

In van der Waals heterostructures (vdWHs), the manipulation of interlayer stacking/coupling allows for the construction of customizable quantum systems exhibiting exotic physics. An illustrative example is the diverse range of states of matter achieved through varying the proximity coupling between two-dimensional (2D) quantum spin liquid (QSL) and superconductors within the TaS2 family. This study presents a demonstration of the intertwined physics of spontaneous rotational symmetry breaking, hidden magnetism, and Ising superconductivity in the three-fold rotationally symmetric, non-magnetic natural vdWHs 6R-TaS2. A distinctive phase emerges in 6R-TaS2 below a characteristic temperature (T*) of approximately 30 K, which is characterized by a remarkable set of features, including a giant extrinsic anomalous Hall effect (AHE), Kondo screening, magnetic field-tunable thermal hysteresis, and nematic magneto-resistance. At lower temperatures, a coexistence of nematicity and Kondo screening with Ising superconductivity is observed, providing compelling evidence of hidden magnetism within a superconductor. This research not only sheds light on unexpected emergent physics resulting from the coupling of itinerant electrons and localized/correlated electrons in natural vdWHs but also emphasizes the potential for tailoring exotic quantum states through the manipulation of interlayer interactions.