Evolution of one-dimensional Cs chains on InAs(110) as determined by scanning-tunneling microscopy and core-level spectroscopy

We present a combined scanning tunneling microscopy and ultraviolet photoelectron spectroscopy investigation on the formation and evolution of one-dimensional (1D) Cs chains on the InAs(110) surface. At 40% of saturation coverage, the linear phase evolves into a two-dimensional (2D) cluster layer. Each Cs nanowire, several hundreds of angstroms long, is aligned along the [11̄0] direction. The Cs chain phase presents different adsorption sites, as deduced by the Cs 5p core-level lineshape and STM. The coverage dependence of the mean interchain distance shows that the Cs nanowires repel each other in the [001] direction, even when they are about 50 Å apart. A repulsive long-range dipole-like interaction influences the mesoscopic properties of the chain phase. The binding energy shift of the Cs core levels can be quantitatively explained, taking into account the Cs depolarization as a function of the chain–chain distance.