Topologization of \u03b2-antimonene on Bi2Se3 via proximity effects

K Holtgrewe,P M Sheverdyaeva,C Hogan,A Barla,E V Chulkov,S Sanna,R Flammini,P Moras,M B Babanly,Z S Aliev,M Papagno,L Petaccia,S Colonna,F Ronci,C Carbone,S K Mahatha

doi:10.1038/s41598-020-71624-4

Abstract

Topological surface states usually emerge at the boundary between a topological and a conventional insulator. Their precise physical character and spatial localization depend on the complex interplay between the chemical, structural and electronic properties of the two insulators in contact. Using a lattice-matched heterointerface of single and double bilayers of β-antimonene and bismuth selenide, we perform a comprehensive experimental and theoretical study of the chiral surface states by means of microscopy and spectroscopic measurements complemented by first-principles calculations. We demonstrate that, although β-antimonene is a trivial insulator in its free-standing form, it inherits the unique symmetry-protected spin texture from the substrate via a proximity effect that induces outward migration of the topological state. This “topologization” of β-antimonene is found to be driven by the hybridization of the bands from either side of the interface.

Highlights

Topological surface states usually emerge at the boundary between a topological and a conventional insulator
We demonstrated a novel procedure for synthesizing large areas of lattice-matched β-antimonene on Bi2Se3 by means of a controlled structural transition from the α to the β p hase[25,26]
From analysis of the integrated local density of states (LDOS), we find that T SSSb strongly contributes to the 1 BL and 2 BL STM images reported in Fig. 3a,e

Summary

Introduction

Topological surface states usually emerge at the boundary between a topological and a conventional insulator. Β-antimonene is a trivial insulator in its free-standing form, it inherits the unique symmetry-protected spin texture from the substrate via a proximity effect that induces outward migration of the topological state This “topologization” of β-antimonene is found to be driven by the hybridization of the bands from either side of the interface. A conventional insulator (CI) and a TI, sharing similar electronic structure in the bulk, at their interface feature a gap closing due to the different topological invariants[2] This process typically occurs via the emergence of metallic topological surface states (TSS), when spatially moving from the CI to the TI. 1 BL and 2 BL of β-antimonene are trivial insulators[31] while showing an important SOC as in the case of bismuth This results in a simpler electronic structure, whose spin texture can be understood by atomistic calculations. This is of paramount importance in applications exploiting the electron spin, as tailoring the CI/TI spin textures can boost the realization of spintronics devices

Methods

Results

Conclusion