Direct Observation of Narrow Electronic Energy Band Formation in 2D Molecular Self-assembly

Overview

Journal Nanoscale Adv

Publisher Royal Society of Chemistry

Specialty Biotechnology

Date 2022 Sep 22

PMID 36133344

Authors

Jack Hellerstedt

Marina Castelli

Anton Tadich

Antonija Grubisic-cabo

Dhaneesh Kumar

Benjamin Lowe

Spiro Gicev

Dionysios Potamianos

Maximilian Schnitzenbaumer

Pascal Scigalla

Simiam Ghan

Reinhard Kienberger

Muhammad Usman

Agustin Schiffrin

Affiliations

Soon will be listed here.

Abstract

Surface-supported molecular overlayers have demonstrated versatility as platforms for fundamental research and a broad range of applications, from atomic-scale quantum phenomena to potential for electronic, optoelectronic and catalytic technologies. Here, we report a structural and electronic characterisation of self-assembled magnesium phthalocyanine (MgPc) mono and bilayers on the Ag(100) surface, low-temperature scanning tunneling microscopy and spectroscopy, angle-resolved photoelectron spectroscopy (ARPES), density functional theory (DFT) and tight-binding (TB) modeling. These crystalline close-packed molecular overlayers consist of a square lattice with a basis composed of a single, flat-adsorbed MgPc molecule. Remarkably, ARPES measurements at room temperature on the monolayer reveal a momentum-resolved, two-dimensional (2D) electronic energy band, 1.27 eV below the Fermi level, with a width of ∼20 meV. This 2D band results from in-plane hybridization of highest occupied molecular orbitals of adjacent, weakly interacting MgPc's, consistent with our TB model and with DFT-derived nearest-neighbor hopping energies. This work opens the door to quantitative characterisation - as well as control and harnessing - of subtle electronic interactions between molecules in functional organic nanofilms.

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