CuTe chains on Cu(111) by deposition of 1/3 ML Te: atomic and electronic structure

TL;DR

This study reveals that depositing 1/3 ML Te on Cu(111) forms Cu$_2$Te$_2$ chains with a specific superstructure, rather than a surface alloy, and characterizes their atomic and electronic structures using multiple advanced techniques.

Contribution

It provides the first detailed atomic and electronic structure analysis of CuTe chains on Cu(111), challenging previous assumptions of alloy formation.

Findings

Te forms Cu$_2$Te$_2$ chains, not a surface alloy.

The superstructure is identified as (2√3 × √3)R30°.

Surface electronic states include anisotropic and isotropic dispersing resonances.

Abstract

The surface atomic and electronic structure after deposition of 1/3 monolayer (ML) 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 Cu$_2$Te$_2$ adsorbate chains in a $\left(2\sqrt{3} \times \sqrt{3}\right)\textrm{R30}^\circ$ 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 $E-E_F = + 1.43\,\textrm{eV}$. Both states coexist with bulk states of the projected band structure and are therefore surface resonances.