Higher-dimensional Fermiology in bulk moiré metals

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Moiré materials, typically van der Waals heterostructures, are crucial for engineering quantum phases but usually synthesized far from thermodynamic equilibrium.
• Existing moiré materials enable studies of correlated electronic phenomena, ferroelectricity, magnetism, and superconductivity.
• Their aperiodic, composite crystal nature allows tunable properties via superlattices without chemical alteration.

Purpose of the Study:

• To introduce a novel approach for synthesizing high-mobility moiré materials under thermodynamic equilibrium conditions.
• To report a new family of foliated superlattice materials with tunable moiré superlattices.
• To explore the complex electronic properties and potential applications of these bulk moiré metals.

Main Methods:

• Synthesis of foliated superlattice materials (Sr6TaS8)1+δ(TaS2)8 in thermodynamic equilibrium.
• Utilizing lattice mismatches between alternating van der Waals layers to generate coherent moiré superlattices.
• Employing quantum oscillation measurements to probe the electronic Fermiology and Fermi surface characteristics.

Main Results:

• Discovery of a new family of exfoliatable, incommensurate-lattice, van der Waals crystals exhibiting moiré superlattices.
• Demonstration of tunable moiré superlattices through synthesis conditions without chemical modification.
• Quantum oscillation data revealing complex Fermiology with over 40 distinct Fermi surface cross-sectional areas in the simplest moiré metal.

Conclusions:

• Bulk moiré metals can encode electronic properties analogous to higher-dimensional superspace crystals.
• The developed scalable synthesis approach holds promise for producing large-area moiré materials for electronics.
• This work presents a new material design concept for exploring phenomena in higher dimensions.