Hidden Order and Haldane-Like Phase in Molecular Chains Assembled from Conformation-Switchable Molecules

Area of Science:

• Condensed Matter Physics
• Materials Science
• Supramolecular Chemistry

Background:

• Topological properties of matter are crucial for scientific and technological advancements.
• Discovering analogs of topological phases in molecular systems is a significant challenge.
• Mimicking key constituents of topological phases in molecular architectures is essential.

Purpose of the Study:

• To explore molecular architectures that exhibit topological properties.
• To demonstrate a molecular analog of the Haldane phase, a topological phase.
• To investigate the potential of conformation-switchable molecules in creating novel topological states.

Main Methods:

• Utilizing scanning tunneling microscopy (STM) to characterize molecular assemblies.
• Assembling quasi-1D molecular chains from conformation-switchable dibenzo[g,p]chrysene molecules.
• Mimicking quantum spin-1 chain properties using molecular chirality and intermolecular interactions.

Main Results:

• Demonstrated hidden antiparallel order in quasi-1D molecular chains.
• Established an analogy between the observed molecular order and the hidden antiferromagnetic order in the Haldane phase.
• Successfully mimicked the spin degree of freedom using intramolecular helicene chiral switches.
• Emulated interspin antiferromagnetic coupling via intermolecular homochiral coupling.

Conclusions:

• The study presents a molecular analog of topological matter.
• The findings pave the way for designing molecular architectures with nontrivial topological properties.
• This work inspires future research into molecular topological phases and their applications.