# Surface resonance of the (2$\times$1) reconstructed lanthanum hexaboride (001)-cleavage plane: a combined STM and DFT study

## TL;DR

This study combines STM, DFT, and LEED to analyze the short-range ordered (2×1) reconstructed surface of LaB6 (001), revealing a labyrinth pattern and identifying a surface resonance dominated by boron and lanthanum states.

## Contribution

It provides a detailed atomic-scale characterization of LaB6 (001) surface reconstruction and identifies the electronic surface resonance using combined experimental and theoretical methods.

## Key findings

- Short-range (2×1) reconstruction observed by STM and LEED.
- Labyrinth-like pattern forms away from step edges.
- Surface resonance identified as boron dangling bonds and lanthanum d-states.

## Abstract

We performed a combined study of the (001)-cleavage plane of lanthanum hexaboride (LaB$_\text{6}$) using scanning tunneling microscopy (STM) and density functional theory (DFT). Experimentally, we found a (2$\times$1) reconstructed surface on a local scale. The reconstruction is only short-range ordered and tends to order perpendicularly to step edges. At larger distances from surface steps, the reconstruction evolves to a labyrinth-like pattern. These findings are supported by low-energy electron diffraction (LEED) experiments. Slab calculations within the framework of DFT shows that the atomic structure consists of parallel lanthanum chains on top of boron octahedra. Scanning tunneling spectroscopy (STS) shows a prominent spectral feature at -0.6 eV. Using DFT, we identify this structure as a surface resonance of the (2$\times$1) reconstructed LaB$_\text{6}$ (100)-surface which is dominated by boron dangling bond-states and lanthanum d-states.