Metal Single Atoms Beyond Catalysis as Quantum Modulators for Programmable Electronic Structures and Adaptive Electronics.

Metal single atoms have long been recognized for their catalytic activity through strong local interactions with host substrates. Beyond catalysis, their potential to reconfigure substrate electronic structures surpassing the host's intrinsic limits remains largely unexplored. Here, we develop an atomically engineered band-modulation strategy, in which representative d-series (Fe, Co, Ni, Cu) and p-series (In, Sn, Sb, Te) atoms are anchored on 2D frameworks, including MXenes, graphene, g-C3N4, and MoS2. These atoms act as quantum modulators, precisely reconfiguring substrate structures and inducing anomalous quantum effects, which yield distinctive phenomena, including band inversion, flattening, and van Hove singularities, features rarely attainable through conventional band-engineering strategies. The tailored electronic landscape enables linear, voltage-driven tuning of electrical behavior, achieving several tens of times enhancement in dielectric permittivity and a dynamic and continuous transition from semiconducting to conductive states, all realized under an exceptionally low bias (<1.0 V). These functionalities are extended to a flexible electromagnetic switch that achieves programmable control of signal transmission, absorption, and reflection, overcoming the persistent difficulty of dynamic electromagnetic regulation while operating at a record-thin microscale thickness (∼600 µm). This work establishes an atomically engineered band-modulation strategy as a versatile platform, paving the way for reconfigurable electronics and quantum devices.