  Using low-temperature scanning tunneling microscopy, we demonstrate an
unambiguous 1-D system that surprisingly undergoes a CDW instability on a
metallic substrate. Our ability to directly and quantitatively measure the
structural distortion of this system provides an accurate reference for
comparison with first principles theory. In comparison to previously proposed
physical mechanisms, we attribute this particular 1-D CDW instability to a
ferromagnetic state. We show that though the linear arrayed dimers are not
electronically isolated, they are magnetically independent, and hence can
potentially serve as a binary spin-memory system.
