Growth of 2D topological material Bi on InSb(111)B with fractal surface structures

TL;DR

This study investigates the growth and electronic properties of 2D topological Bi layers on InSb(111)B, revealing layer-by-layer growth up to four layers with fractal surface structures and transitions to 3D islands, offering insights into topological electronic states.

Contribution

It demonstrates the growth process and surface structures of Bi on InSb(111)B, including the formation of fractal patterns and the evolution of electronic states during layer deposition.

Findings

Single-layer Bi exhibits Sierpiński-triangle fractal patterns.

Layer-by-layer growth of Bi up to four atomic layers.

Transition to 3D island growth upon further Bi evaporation.

Abstract

Bismuth (Bi) atomic layers are known as 2D topological materials with variety of the electronic structures and topological orders depending on the number of stacking layers. Recently, it is reported that few layers of Bi grown on semiconductor substrate InSb(111)B exhibit the Sierpi\'{n}ski-triangle (ST) fractal patterns on the surface. In this work, we have grown Bi layers on InSb(111)B and traced the evolution of the atomic and electronic structures of Bi. The surface atomic structures and growth modes were monitored by using reflective high-energy electron diffraction and core-level photoelectron spectroscopy. It is suggested that the single layer of the ST-phase Bi grows on InSb(111)B and the following Bi deposition causes layer-by-layer growth up to nominally 4 atomic layers. Diffuse band dispersion and quantum well states observed by angle-resolved photoelectron spectroscopy are consistent with the small surface domains and variation of the thickness even during the layer-by-layer growth region. The further Bi evaporation changes the growth mode to the 3D island formation. The unveiled growth behavior of Bi on InSb(111)B would provide a new interesting playground to study 2D topological electronic structure of quasi-periodic 2D atomic layers.