  It has been a long-standing goal to create magnetism in a nonmagnetic
material by manipulating its structure at the nanometer scale. This idea may be
realized in graphitic carbon: evidence suggests magnetic states at the edges of
graphene ribbons and at grain boundaries in graphite. Such phenomena have long
been regarded as unlikely in silicon because there is no graphitic bulk phase.
Here we show theoretically that intrinsic magnetism indeed exists in a class of
silicon surfaces whose step edges have a nanoscale graphitic structure. This
magnetism is intimately connected to recent observations, including the
coexistence of double- and triple-period distortions and the absence of edge
states in photoemission. Magnetism in silicon may ultimately provide a path
toward spin-based logic and storage at the atomic level.
