  We report the first experimental generation and observation of Airy beams of
free electrons. The electron Airy beams are generated by diffraction of
electrons through a nanoscale hologram, that imprints a cubic phase modulation
on the beams' transverse plane. We observed the spatial evolution dynamics of
an arc-shaped, self accelerating and shape preserving electron Airy beams. We
directly observed the ability of electrons to self-heal, restoring their
original shape after passing an obstacle. This electromagnetic method opens up
new avenues for steering electrons, like their photonic counterparts, since
their wave packets can be imprinted with arbitrary shapes or trajectories.
Furthermore, these beams can be easily manipulated using magnetic or electric
potentials. It is also possible to efficiently self mix narrow beams having
opposite signs of acceleration, hence obtaining a new type of electron
interferometer.
