  We found that magnetic ground state of one-dimensional atomic chains of
carbon-transition metal compounds exhibit half-metallic properties. They are
semiconductors for one spin-direction, but show metallic properties for the
opposite direction. The spins are fully polarized at the Fermi level and net
magnetic moment per unit cell is an integer multiple of Bohr magneton. The
spin-dependent electronic structure can be engineered by changing the number of
carbon and type of transition metal atoms. These chains, which are stable even
at high temperature and some of which keep their spin-dependent electronic
properties even under moderate axial strain, hold the promise of potential
applications in nanospintronics.
