Direct observation of many-body charge density oscillations in a two-dimensional electron gas

作者：Sessi Paolo^*; Silkin Vyacheslav M; Nechaev Ilya A; Bathon Thomas; El Kareh Lydia; Chulkov Evgueni V; Echenique Pedro M; Bode Matthias

来源：Nature Communications, 2015, 6(1): 8691.

DOI：10.1038/ncomms9691

Quantum interference is a striking manifestation of one of the basic concepts of quantum mechanics: the particle-wave duality. A spectacular visualization of this effect is the standing wave pattern produced by elastic scattering of surface electrons around defects, which corresponds to a modulation of the electronic local density of states and can be imaged using a scanning tunnelling microscope. To date, quantum-interference measurements were mainly interpreted in terms of interfering electrons or holes of the underlying band-structure description. Here, by imaging energy-dependent standing-wave patterns at noble metal surfaces, we reveal, in addition to the conventional surface-state band, the existence of an 'anomalous' energy band with a well-defined dispersion. Its origin is explained by the presence of a satellite in the structure of the many-body spectral function, which is related to the acoustic surface plasmon. Visualizing the corresponding charge oscillations provides thus direct access to many-body interactions at the atomic scale.

• 出版日期2015-10