Termination-dependent surface properties in the giant-Rashba semiconductors BiTeX (X = Cl, Br, I)

TL;DR

This study investigates the surface structures and electronic properties of BiTeX (X = Cl, Br, I) semiconductors with large Rashba spin-orbit splitting, revealing differences in termination and homogeneity relevant for spintronics applications.

Contribution

It provides a systematic analysis combining STM, ARPES, XPS, and DFT to understand termination-dependent surface properties of BiTeX semiconductors.

Findings

BiTeCl and BiTeBr have macroscopic single-terminated surfaces

BiTeI surfaces are inhomogeneous with stacking faults

Chemical bonding and surface morphology vary among the three materials

Abstract

The non-centrosymmetric semiconductors BiTeX (X = Cl, Br, I) show large Rashba-type spin-orbit splittings in their electronic structure making them candidate materials for spin-based electronics. However, BiTeI(0001) single crystal surfaces usually consist of stacking-fault-induced domains of Te and I terminations implying a spatially inhomogeneous electronic structure. Here we combine scanning tunneling microscopy (STM), photoelectron spectroscopy (ARPES, XPS) and density functional theory (DFT) calculations to systematically investigate the structural and electronic properties of BiTeX(0001) surfaces. For X = Cl, Br we observe macroscopic single-terminated surfaces. We discuss chemical characteristics among the three materials in terms of bonding character, surface electronic structure, and surface morphology.