Critical behavior at chiral melting: Disordering of the Si(113)-(3×1) reconstruction

Results of an x-ray-scattering study of the (3×1)-to-disordered phase transformation of the Si(113) surface are reported. A continuous commensurate-solid to incommensurate-fluid transformation occurs at ${\mathit{T}}_{\mathit{c}}$=959 K. A new two-dimensional universality class is identified and characterized. Specifically, we find that the correlation lengths in the disordered phase scale anisotropically, and that the product of the incommensurability and the correlation length along the incommensurate direction is constant.