Surface structure of Bi2Se3(111) determined by low-energy electron diffraction and surface X-ray diffraction

TL;DR

This study precisely characterizes the surface structure of Bi2Se3(111) using electron and X-ray diffraction, confirming an intact quintuple layer termination and small surface relaxations at room temperature.

Contribution

It provides a detailed surface structural analysis of Bi2Se3(111) using complementary diffraction techniques, ruling out alternative terminations and quantifying surface relaxations.

Findings

Surface terminated by an intact quintuple layer

No evidence for bismuth bilayer termination

Small surface relaxations consistent across techniques

Abstract

The surface structure of the prototypical topological insulator Bi2Se3 is determined by low-energy electron diffraction and surface X-ray diffraction at room temperature. Both approaches show that the crystal is terminated by an intact quintuple layer. Specifically, an alternative termination by a bismuth bilayer is ruled out. Surface relaxations obtained by both techniques are in good agreement with each other and found to be small. This includes the relaxation of the van der Waals gap between the first two quintuple layers.