Layer-dependent local gate response in graphene-supported TaSe₂ films studied by gate-tunable STM

Gate-tunable scanning tunnelling microscopy (STM) enables direct correlation between electrostatic gating and local electronic states in two-dimensional correlated materials. Here, we investigate TaSe_2 films on graphene using a home-built gate-tunable STM setup. Large-area and atomically resolved STM images reveal well-defined TaSe_2 islands and an ordered charge-density-wave (CDW) superstructure. Monolayer TaSe_2 shows spatially resolved scanning tunnelling spectroscopy (STS) features but a strongly suppressed gate response under back-gate voltages. In contrast, bilayer TaSe_2 exhibits a richer zero-gate electronic structure and systematic bias-dependent evolution of CDW contrast. Fixed-point gate-dependent STS in the bilayer region demonstrates clear spectral-weight redistribution and low-energy feature evolution. Our results establish a feasible gate-tunable STM protocol for TaSe_2/graphene heterostructures and reveal pronounced layer-dependent local gate response in correlated two-dimensional systems.