Contactless electronic compressibility measurements of few-layer WSe₂

Over the past decade, the discovery of intriguing quantum phenomena such as non-trivial topology, superconductivity, and quantum Hall effects have generated intense interest in layered transition metal dichalcogenides (TMDs). Unlike in graphene, poor contacts have impeded the thorough study of TMD systems at millikelvin temperatures. We have developed a novel “contactless capacitance” method to circumvent the issue of poor contacts and enable compressibility and charge transport measurements on these materials at very low temperatures and carrier densities inaccessible to current electronic measurement techniques. We demonstrate our new technique on mono- and few-layer WSe₂ flakes, demonstrating high device quality and our ability to measure delicate quantum phenomena without the need for low-resistance contacts.