Observation of Charge-Density Wave Domains on the Cr(110) Surface by Low-Temperature Scanning Tunneling Microscopy

We have studied the Cr(110) surface with low-temperature scanning tunneling microscopy at 6 to 145 K. For tunneling voltages below $\pm 150\mathrm{mV}$ we observe a surface charge-density wave (CDW) with a wavelength of $42Å$ and wave fronts aligned with the [001] in-plane direction. The observed wave pattern is identified as the surface projection of the bulk CDW's arising from the spin-density wave ground state of Cr with the $\mathbf{Q}$ vector parallel to [100] and [010], respectively. The bulk CDW with $\mathbf{Q}$ parallel to the [001] in-plane direction appears, however, to be strongly suppressed at the Cr(110) surface.