Unidirectional Kondo scattering in layered NbS2

Crystalline defects can modify quantum interactions in solids, causing unintuitive, even favourable, properties such as quantum Hall effect or superconducting vortex pinning. Here we present another example of this notion-an unexpected unidirectional Kondo scattering in single crystals of 2H-NbS2. This manifests as a pronounced low-temperature enhancement in the out-of-plane resistivity and thermopower below 40 K, hidden for the in-plane charge transport. The anomaly can be suppressed by the c-axis-oriented magnetic field, but is unaffected by field applied along the planes. The magnetic moments originate from layers of 1T-NbS2, which inevitably form during the growth, undergoing a charge-density-wave reconstruction with each superlattice cell (David-star-shaped cluster of Nb atoms) hosting a localised spin. Our results demonstrate the unique and highly anisotropic response of a spontaneously formed Kondo-lattice heterostructure, intercalated in a layered conductor.

Automated summary

Crystalline defects can alter quantum interactions in solids, leading to unexpected phenomena such as unidirectional Kondo scattering in single crystals of 2H-NbS2. This scattering manifests as enhanced out-of-plane resistivity and thermopower at low temperatures, suppressed by a c-axis-oriented magnetic field. The magnetic moments originate from layers of 1T-NbS2, forming during growth and contributing to the unique and highly anisotropic response of the Kondo-lattice heterostructure in a layered conductor.