A New Three-Dimensional Subsulfide Ir₂In₈S with Dirac Semimetal Behavior

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Physics

Background:

• Dirac and Weyl semimetals possess unique quasiparticles with exceptional transport characteristics.
• Numerous topological semimetals are predicted, but experimental validation is often hindered by synthesis challenges or phase instability.

Purpose of the Study:

• To synthesize and characterize a new type-II Dirac semimetal, Ir2In8S.
• To investigate its structural, electronic, and transport properties for potential applications in topological materials research.

Main Methods:

• Crystal growth of Ir2In8S.
• Electronic structure calculations to identify Dirac crossings.
• Transport measurements, including magnetoresistance and Shubnikov-de Haas oscillations.

Main Results:

• Successfully synthesized the air-stable, type-II Dirac semimetal Ir2In8S with a novel structure type.
• Observed two Dirac crossings along the Γ-Z direction.
• Measured high electron carrier mobility (~10,000 cm^2/(V s)) and large, nonsaturating transverse magnetoresistance (~6000%).
• Shubnikov-de Haas oscillations indicated small Fermi pockets and a possible nontrivial Berry phase.

Conclusions:

• Ir2In8S is a new material system for studying topological semimetals.
• Its facile synthesis and unique properties offer advancements in the field of topological materials.