Ultrafast Coherent Electron Transfer through Intermolecular Quantum Well States

Area of Science:

• Molecular materials science
• Quantum electronics
• Surface science

Background:

• Molecular materials are crucial for light absorption and charge transport in natural and artificial systems.
• Quantum coherence enhances photoexcitation and charge transfer but is susceptible to environmental decoherence.
• Engineered molecular architectures are needed to harness quantum effects for advanced applications.

Purpose of the Study:

• To create and investigate a nanoporous molecular system for coherent electron transport.
• To explore the role of molecule-dressed vacuum in preserving quantum coherence.
• To establish a new paradigm for quantum state design in molecular architectures.

Main Methods:

• Assembled a nanoporous medium of bipyridyl ethylene (BPE) molecules on a Ag(111) surface.
• Utilized time-periodic driving with femtosecond pulses to create Floquet quasi-energy donor states.
• Employed interferometric time- and angle-resolved multiphoton photoemission spectroscopy to observe electron transport.

Main Results:

• Demonstrated coherent electron wave conduction over 20 angstroms within the BPE array.
• Observed preservation of quantum coherence on a ~150 fs timescale due to electron decoupling from the metal substrate.
• Identified a molecule-dressed vacuum acting as a quantum well conductor.

Conclusions:

• A nanoporous molecular system can act as an exceptional conductor of coherent electron waves.
• Molecule-dressed vacuum environments can significantly preserve quantum coherence.
• This work presents a new strategy for designing quantum states and coherent electron transport in molecular architectures.