  Interest in two dimensional materials has exploded in recent years. Not only
are they studied due to their novel electronic properties, such as the emergent
Dirac Fermion in graphene, but also as a new paradigm in which stacking layers
of distinct two dimensional materials may enable different functionality or
devices. Here, through first-principles theory, we reveal a large new class of
two dimensional materials which are derived from traditional III-V, II-VI, and
I-VII semiconductors. It is found that in the ultra-thin limit all of the
traditional binary semi-conductors studied (a series of 26 semiconductors)
stabilize in a two dimensional double layer honeycomb (DLHC) structure, as
opposed to the wurtzite or zinc-blende structures associated with three
dimensional bulk. Not only does this greatly increase the landscape of
two-dimensional materials, but it is shown that in the double layer honeycomb
form, even ordinary semiconductors, such as GaAs, can exhibit exotic
topological properties.
