CuTe chains on Cu(111) by deposition of one-third of a monolayer of Te: Atomic and electronic structure

Abstract

The surface atomic and electronic structure after deposition of one-third of a monolayer Te on Cu(111) was determined using a combination of low-energy electron diffraction (LEED), scanning tunneling microscopy and spectroscopy (STM/STS), angle-resolved single and two-photon photoelectron spectroscopy (ARPES /AR-2PPE), and density functional theory (DFT) calculations. Contrary to the current state in literature, Te does not create a two-dimensional surface alloy but forms ${\mathrm{Cu}}_{2}{\mathrm{Te}}_{2}$ adsorbate chains in a $\left(2\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}\right){\text{R30}}^{\ensuremath{\circ}}$ superstructure. We establish this by a high-precision LEED-IV structural analysis with Pendry $R$ factor of $R=0.099$ and corroborating DFT and STM results. The electronic structure of the surface phase is dominated by an anisotropic downward dispersing state at the Fermi energy ${E}_{F}$ and a more isotropic upward dispersing unoccupied state at $E\ensuremath{-}{E}_{F}=+1.43\phantom{\rule{0.16em}{0ex}}\text{eV}$. Both states coexist with bulk states of the projected band structure, and are therefore surface resonances.