All atoms in nature are moving because they are at a temperature higher than 0 [0K], thus they have thermal energy.
At low temperatures, it is possible to almost stop atoms by using the momentum of the photons of the laser radiation.
Explanation:
A beam of laser light moving in the opposite direction of a beam of atoms can be made to interact with each other in such a way that the atoms absorb photons from the laser beam. The process occurs when the photons energy (which is determined by the photon frequency) is exactly equal to the energy difference between energy levels of these atoms.
When the atom is in motion, then by the Doppler effect this atom "sees" a slightly different frequency of the incoming photons.
By using a few beams from opposite directions, it is possible to stop the movement of atoms.
The frequency of the laser beam is chosen such that it is very close to the absorption frequency of the atom, but not identical to it. Each time the atom starts to move toward one of the laser beams, the Doppler effect causes the radiation from that beam to be absorbed by the atom, so it returns to its place.