Hybrid 2D Semimetal Heterostructures of Graphene and WTe₂: Part 2

In 2D semimetals, the coexistence of small electron and hole pockets, combined with reduced screening, can lead to strongly correlated phenomena. For example, monolayer WTe₂ demonstrates low temperature characteristics that have been attributed to an excitonic insulator state, including a charge gap that appears to be many-body in nature. As explored in the first half of our presentation, combining WTe₂ with graphene creates a hybrid 2D semimetal which has transport characteristics unique from either of its constituent materials. In this second half of our presentation, we present our magnetotransport studies of hybrid devices using both monolayer and bilayer graphene, revealing a number of features and puzzles. These include spontaneous charge transfer between materials, non-quantized Hall plateaus, the persistence of the WTe₂ gap, and signatures of weak anti-localization, suggestive of induced spin-orbit coupling in the bilayer graphene case. To further investigate the remaining WTe₂ gap, we use a monolayer graphene sensor in parallel to measure the chemical potential of the hybrid material.