Gate-Defined One-Dimensional Channel and Broken Symmetry States in MoS2 van der Waals Heterostructures

We have realized encapsulated trilayer MoS 2 devices with gated graphene contacts. In the bulk, we observe an electron mobility as high as 7000 cm 2 /(V s) at a density of 3 × 10 12 cm –2 at a temperature of 1.9 K. Shubnikov–de Haas oscillations start at magnetic fields as low as 0.9 T. The observed 3-fold Landau level degeneracy can be understood based on the valley Zeeman effect. Negatively biased split gate electrodes allow us to form a channel that can be completely pinched off for sufficiently large gate voltages. The measured conductance displays plateau-like features.