Probing the Electronic Properties of Individual MnPc Molecules Coupled to Topological States

TL;DR

This study investigates the interaction between MnPc molecules and Bi2Te3 topological insulator surfaces, revealing stable binding, minimal charge transfer, unaffected topological states, and the emergence of hybrid states, opening avenues for novel hybrid heterostructures.

Contribution

It provides the first detailed STM/STS analysis of MnPc molecules on Bi2Te3, demonstrating stable adsorption and the formation of hybrid states without disrupting topological surface states.

Findings

MnPc binds stably via its Mn atom

Topological states remain unaffected by molecules

Hybrid states emerge from molecule-substrate interaction

Abstract

Hybrid organic/inorganic interfaces have been widely reported to host emergent properties that go beyond those of their single constituents. Coupling molecules to the recently discovered topological insulators, which possess a linearly dispersing and spin-momentum--locked Dirac fermions, may offer a promising platform towards new functionalities. Here, we report a scanning tunneling microscopy and spectroscopy study of the prototypical interface between MnPc molecules and a Bi$_2$Te$_3$ surface. MnPc is found to bind stably to the substrate through its central Mn atom. The adsorption process is only accompanied with a minor charge transfer across the interface, resulting in a moderately n-doped Bi$_2$Te$_3$ surface. More remarkably, topological states remain completely unaffected by the presence of the molecules, as evidenced by the absence of scattering patterns around adsorption sites. Interestingly, we show that, while the HOMO and LUMO orbitals closely resembles those of MnPc in the gas phase, a new hybrid states emerges through interaction with the substrate. Our results pave the way towards hybrid organic--topological insulator heterostructures, which may unveil a broad range of exciting and unknown phenomena.