High temperature quantum transport in 2D moiré superlattices

Van der Waals heterostructures based on moiré superlattices have become increasingly popular due to their large tunability unprecedented by any other solid-state system. In this talk, we review recent experimental results on high-temperature electron transport studies in heterostructures based on 2D moiré superlattices. Our experiments describe two fundamental phenomena of electron transport that manifest profoundly at high temperatures and are extremely sensitive to the twist-angle. First, we show that electron-electron collisions in graphene superlattices are dominated by umklapp processes [1]. They cause a giant increase in resistivity that grows rapidly upon decreasing the twist-angle between 2D layers, degrading the intrinsic mobility of graphene by more than an order of magnitude. Second, we show that moiré superlattices feature a novel class of quantum magnetoresistance oscillations [2] that differ fundamentally from the Shubnikov de Haas effect and all known quantum oscillatory phenomena.

[1] J. Wallbank, R. Krishna Kumar et al. Nature Physics (2018)
[2] R. Krishna Kumar, et al. PNAS. 115 , 5135-5139 (2018)