Dresden 2009 – wissenschaftliches Programm
DS 9.2: Vortrag
Dienstag, 24. März 2009, 09:45–10:00, GER 37
A Quantum-stabilized Mirror for Atoms — Daniel Barredo1, Fabián Calleja1, Pablo Nieto1, Juan José Hinarejos1, Guillaume Laurent1, Amadeo Vázquez de Parga1, •Daniel Farías1, and Rodolfo Miranda1,2 — 1Dpto. Física de la Materia Condensada, Universidad Autónoma de Madrid, Spain — 2Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Spain
Helium atom scattering is a well-established technique for investigating the structural and dynamical properties of surfaces. Because of the low energies used (100 meV), neutral He atoms probe the topmost surface layer of any material in an inert, completely nondestructive manner. This means that a Scanning Helium Atom Microscope using a focused beam of He atoms would be a unique tool for reflection or transmission microscopy, with a potential lateral resolution of ca. 50 nm. It could be used to investigate insulating glass surfaces, delicate biological materials and fragile samples which are difficult to examine by other methods. However, the practical realization of such a microscope requires the development of a mirror able to focus a beam of low energy He atoms into a small spot on the sample.
Here we show that Quantum Size Effects can be exploited to produce an ultraperfect, atomically flat film of Pb of magic thickness on a highly perfect Si(111) thin wafer. The metal film reproduces the structural perfection of the substrate, is atomically flat over micron-wide areas and stable up to 250 K. As a consequence, more than 15% of the incoming He atoms are scattered into the specular direction, which allows its use as an ultra smooth mirror for neutral atoms.