Self-assembly of tetracyanonaphtho-quinodimethane (TNAP) based metal-organic networks on Pb(111): Structural, electronic, and magnetic properties

TL;DR

This study investigates the structural, electronic, and magnetic properties of TNAP-based metal-organic networks on Pb(111) using microscopy and spectroscopy, revealing diverse bonding motifs and magnetic interactions with superconducting surfaces.

Contribution

It provides new insights into the formation, structure, and magnetic interactions of TNAP-based networks on superconducting Pb(111) surfaces, including the observation of Shiba states.

Findings

Formation of densely packed TNAP islands at low temperatures.

Creation of long-range ordered porous structures with Pb adatoms.

Observation of Shiba states indicating magnetic interactions.

Abstract

We use scanning tunneling microscopy and spectroscopy to investigate structural and electronic properties of tetracyanonaphtho-quinodimethane (TNAP) based metal-organic networks on a superconducting Pb(111) surface. At low temperatures, the TNAP molecules form densely packed islands. When deposited at room temperature, Pb adatoms are incorporated into fourfold bonding nodes with the TNAP molecules leading to long-range ordered porous structures. Co-deposition of NaCl with TNAP yields a Na source for an ionically bonded Na-TNAP structure. Fourfold bonding motifs are also created by Fe atoms with the cyano terminations of TNAP. However, the structures are irregular and do not sustain the formation of long-range ordered networks. Some Fe centers with molecules surrounded in a local C2 symmetry exhibit Shiba states as a fingerprint of a magnetic interaction with the superconducting surface.