Abstract

The prevailing strategy for functionalising quasi-two-dimensional materials is to manipulate the coupling between the atomic sheets to produce novel tunable electronic states with exploitable properties. The responsible interactions can be sensitively gauged by the interlayer charge transport. This property, however, has so far remained largely unexplored due to associated experimental challenges.

By employing focused ion beam microfabrication we were able to conduct unprecedentedly precise measurements of resistivity anisotropy in selected layered transition metal dichalcogenides. In the case of 1T-TaS2 – a compound exhibiting a plethora of diverse phases – we observed a counterintuitive preference toward the out-of-plane conduction. We interpret this unusual behaviour in terms of a charge-density-wave-induced formation of quasi-one-dimensional electronic states extending along the c-axis of the crystal. Our study of the 2H and 3R polytypes of NbS2 revealed that distinct layer stacking orders result in drastically different interlayer charge transport properties. Furthermore, we observed an anomalous minimum in the temperature dependence of the out-of-plane resistivity of 2H-NbS2, as well as an unusual negative longitudinal c-axis magnetoresistance, which we attribute to the prevalence of stacking faults in the material.