On the floating of the topological surface state on top of a thick lead layer: The case of the Pb/Bi2Se3 interface

TL;DR

This study investigates the behavior of topological surface states at the Pb/Bi2Se3 interface, revealing that these states do not float on the Pb layer but are influenced by surface diffusion and tend to move inward.

Contribution

The paper provides new insights into the interface physics of topological states, combining experimental observations with density functional theory calculations.

Findings

Topological surface states do not float on thick Pb layers.

Surface diffusion affects the visibility of topological states.

States tend to move inward within the substrate despite interface arrangements.

Abstract

The puzzling question about the floating of the topological surface state on top of a thick Pb layer, has now possibly been answered. A study of the interface made by Pb on Bi2Se3 for different temperature and adsorbate coverage condition, allowed us to demonstrate that the evidence reported in the literature can be related to the surface diffusion phenomenon exhibited by the Pb atoms, which leaves the substrate partially uncovered. Comprehensive density functional theory calculations show that despite the specific arrangement of the atoms at the interface, the topological surface state cannot float on top of the adlayer but rather tends to move inward within the substrate.