2D honeycomb transformation into dodecagonal quasicrystals driven by electrostatic forces.

Area of Science:

• Materials Science
• Solid-State Chemistry
• Surface Science

Background:

• Dodecagonal oxide quasicrystals exhibit long-range aperiodic order in 2D.
• Their precise atomic structure remains controversial despite extensive investigation.
• Formation principles for oxide quasicrystals differ from metallic systems.

Purpose of the Study:

• To elucidate the atomic structure of dodecagonal oxide quasicrystals.
• To identify the driving forces behind their formation.
• To resolve structural controversies using advanced experimental and theoretical methods.

Main Methods:

• Surface X-ray Diffraction (SXRD) refinement of the largest known approximant.
• Density Functional Theory (DFT) calculations.
• Analysis of atomic arrangements and bonding.

Main Results:

• The oxide quasicrystal structure was solved via SXRD.
• Large alkaline earth metal atoms and reduced electrostatic repulsion drive formation.
• Ti2O3 honeycomb undergoes Stone-Wales transformations into specific ring structures (n=4, 7, 10).

Conclusions:

• The study successfully determined the oxide quasicrystal structure.
• Formation is governed by atomic size and electrostatic interactions, not metallic QC principles.
• Specific ring configurations (empty n=4, singly occupied n=7, doubly occupied n=10) are key features.