Optical anisotropy of Si(111)-( 4x1)/( 8x2)-In nanowires calculated from first-principles

First-principles calculations of the anisotropic optical response of Si(111)-(4x1)(8x2)-In from the mid-infrared to the visible region are compared with recent experimental data. The experimental data show that the anisotropic Drude tail of the (4x1) room-temperature phase is replaced by two peaks at 0.50eV and 0.72eV after the phase transition to the low-temperature (8x2) structure took place. The spectrum calculated from both intraband and interband transitions for the metallic zig-zag chain model of the (4x1) phase accounts well for the room-temperature data. The low-temperature data are well explained on the basis of the semiconducting hexagon (8x2) model by interband transitions mainly from a region close the XM high-symmetry line of the Brillouin zone. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim