Microscopic origins of band topology and correlated states in twisted MoTe2: Part 1

Twisted bilayer molybdenum ditelluride (tMoTe₂) has recently been discovered to host fractional quantum anomalous Hall states, along with other intriguing correlation-driven phases of matter. Various microscopy techniques have been employed to probe the microscopic properties of tMoTe₂, but so far these have been limited to minimum spatial resolution several times larger than the moiré periodicity. Here, we study tMoTe₂ with atomic resolution using scanning tunneling microscopy and spectroscopy (STM/S). In the first part of this presentation, we will discuss the topographic and spectroscopic features of charge-neutral tMoTe₂. By studying samples with twist angles ranging from <1° to >5°, we find that atomic-scale lattice relaxations play a significant role in reconstructing the structure of the moiré pattern over a wide range of superlattice wavelengths. We further employ STS to spatially image the flat-band wavefunctions arising from the K- and Γ-points of the MoTe₂ Brillouin zone. Our measurements in the K-point bands directly probe the out-of-plane component of a layer-pseudospin skyrmion lattice arising due to the combination of atomic lattice relaxations and the broken inversion symmetry of MoTe₂, providing a microscopic connection to the topology of the flat bands. In the second part of this talk, we will discuss efforts to further probe the correlated states in tMoTe₂ with gate-tunable samples.