  Nanoelectromechanical Systems (NEMS) are among the best candidates to measure
interactions at nanoscale [1-6], especially when resonating oscillators are
used with high quality factor [7, 8]. Despite many efforts [9, 10], efficient
and easy actuation in NEMS remains an issue [11]. The mechanism that we
propose, thermally mediated Center Of Mass (COM) displacements, represents a
new actuation scheme for NEMS and MEMS. To demonstrate this scheme efficiency
we show how mechanical nanodis- placements of a MEMS is triggered using
modulated X-ray microbeams. The MEMS is a microswing constituted by a Ge
microcrystal attached to a Si microcantilever. The interaction is mediated by
the Ge absorption of the intensity modulated X-ray microbeam impinging on the
microcrystal. The small but finite thermal expansion of the Ge microcrystal is
large enough to force a nanodisplacement of the Ge microcrystal COM glued on a
Si microlever. The inverse mechanism can be envisaged: MEMS can be used to
shape X-ray beams. A Si microlever can be a high frequency X-ray beam chopper
for time studies in biology and chemistry.
