Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 51: Focus Session: Molecular Nanostructures on Surfaces: On-Surface Synthesis and Single-Molecule Manipulation II
O 51.6: Vortrag
Mittwoch, 20. März 2024, 16:30–16:45, HE 101
Unipolar Resonant Hole Transport Through a Free-Standing Designer Graphene Nanoribbon — •Niklas Friedrich1, Jingcheng Li1, Iago Pozo2, Diego Peña2, and Nacho Pascual1 — 1CIC nanoGune, Spain — 2CiQUS, Spain
Coherent electron transport through individual molecules is a vital technique to probe different quantum mechanical properties like energy level alignment, vibronic modes or spin states. Here, we investigate the electronic transport through 7-armchair graphene nanoribbons (GNRs) containing a single, substitutionally embedded 2B-dimer.
We find that the coherent electron transport through the 2B-GNR is unipolar with a singly occupied 2B-state (O2B) enabling resonant electron tunneling at both voltage polarities. The unipolar transport is favored by an exponential localization of the O2B resulting in a double tunneling barrier configuration. Further transport resonances reveal that resonant transport through the valence band exhibits a unipolar character, too. We find fingerprints of vibronic satellites and of band quantization in form of Fabry-Perot quantum well modes in our experiments.
The experiments were performed by lifting single 2B-GNRs using the tip of a low-temperature scanning tunneling microscope (STM) to create the molecular wires that bridges tip and substrate. Our results unravel the details of coherent resonant electron tunneling through molecular wires built from single 2B-doped GNRs, confirming their technological potential for single molecule electronics.
Keywords: Scanning Tunneling Microscopy; Graphene Nanoribbon; single molecule devices; Two-terminal transport