Energy gap of the spin density wave at the Cr(110) surface

Angle resolved photoemission is used to directly monitor the energy gap of the spin density wave of Cr at a (110) surface. Density functional calculations, including a Fermi surface contour, predict an energy gap in the surface proximity. Surface states are identified, and a near-surface gap of ∼200 meV at room temperature is found, using spectroscopy, extending above the Fermi level. The gap exhibits an increased critical temperature of ∼440 K and extends isotropically around the Γ point.