Strong Interaction Effects Revealed by Landau Levels in Bilayer MoS₂

Two-dimensional semiconducting transition metal dichalcogenides (TMDCs) have been a recent hot topic in physics research, for their novel optical/electronic properties and potential applications. While phenomena such as direct-to-indirect bandgap transition, spin-orbital coupling, and symmetry-controlled valleytronics have attracted wide studies, interaction effect was only reported recently in monolayer WSe₂.
Here we present our research on strong interaction effects of K-valley electrons in bilayer MoS₂. We fabricated h-BN-encapsulated bilayer MoS₂ devices with an outstanding quality, showing a high mobility of 22000cm²/(V.s) at 1.5K and quantized Hall plateaus at high magnetic fields. Shubnikov-de Haas oscillations down to a filling factor of 2, a full spin-polarized regime, and crossings of Landau levels (LLs) were observed. Besides determining a density-dependent g-factor, we discovered other rich physical phenomena in the LL spectrum, including the anti-crossings of LLs, all pointing to a strong electron-electron interaction scenario in this material.