Layer-decoupled electronic reconstruction and a robust charge density wave in GdTe3

Abstract

Two-dimensional van der Waals materials host a variety of intertwined quantum phases, whose deterministic control remains a central challenge. The rare-earth tritellurides ( R Te 3 ), a model system for charge density wave (CDW) physics, offer a unique platform to study the response of a collective electronic order to external perturbations. Here, using angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations, we investigate the electronic structure of GdTe 3 under in-situ potassium deposition. We find that the doped electrons trigger a highly selective, layer-decoupled electronic reconstruction. Bands primarily derived from the Gd-Te slabs accommodate the additional charge, exhibiting large downward energy shifts, while electronic states localized on the Te square-net layers, which host the CDW, remain remarkably inert. This electronic separation is accompanied by a marked reduction in the interlayer hybridization, which indicates a weakening of electronic communication between the layers. This mechanism provides a direct explanation for the observed, anomalous robustness of the CDW, which persists with its characteristic energy gap largely unperturbed despite the significant increase in the global Fermi level. Our findings demonstrate an “internal shielding” mechanism, where one atomic layer accommodates external charge perturbations to protect collective order in an adjacent layer, providing a new approach for selective control in layered materials.