Epitaxial nanocrystals of FeGe have been stabilized on Ge(111). The nanocrystals assume a quasi-one-dimensional shape as they grow exclusively along the $⟨1\overline{1}0⟩$ direction of the Ge(111) substrate, culminating in a compressed monoclinic modification of FeGe. Whereas monoclinic FeGe is antiferromagnetic in the bulk, the nanowires are surprisingly strong ferromagnets below $\sim 200\mathrm{K}$ with an average magnetic moment of $0.8{\mu }_B$ per Fe atom. Density functional calculations indicate an unusual stabilization mechanism for the observed ferromagnetism: lattice compression destabilizes the antiferromagnetic Peierls-like ground state observed in the bulk while increased $p\mathrm{\text{−}}d$ hybridization suppresses the magnetic moments and stabilizes ferromagnetism.

• Received 1 June 2005

DOI:https://doi.org/10.1103/PhysRevLett.96.127201