موجة كثافة شحنة شاذة في موصل فائق ثنائي الأبعاد فائق الذرية ✛ ✦

الملخص الأصلي

كما كتبه المؤلفون، بالإنجليزية arXiv:2606.23490

The spatial modulation of electron density into a wave-like pattern, known as charge density wave (CDW), represents a fundamental quantum state that often coexists with superconductivity, quantum Hall states, axion insulating phases and etc. Conventional CDWs are mediated by longitudinal acoustic phonons, exhibit picometer-scale lattice distortions ($$10^{-12}$$--$$10^{-11}$$ m), and typically vanish approaching the atomic limit. Here, we report a series of anomalous CDW behaviors in the 2D superatomic superconductor Au$$_6$$Te$$_{12}$$Se$$_8$$. Remarkably, its CDW is governed by transverse phonons, accompanied by an extraordinarily high real-space displacement of $$\sim 4$$ \AA ngstr\"om. Furthermore, we observe an exotic dimensional response persisting up to micrometer-scale thickness, a regime where other materials are already considered as bulk. Through liquid helium-temperature transmission electron microscopy, ultrafast pump-probe spectroscopy and transport measurements, we demonstrate a dramatic enhancement of the CDW transition temperature ($$T_{\text{CDW}}$$) from $$<2$$ K in the bulk to 110 K in approaching the ``superatomic limit''. Our findings not only reveal novel facets of both CDW and superatomic materials, but the competition between this anomalous CDW and superconductivity opens avenues for exploring unconventional electron-phonon interactions.