IrGe₄: A Predicted Weyl-Metal with a Chiral Crystal Structure

Area of Science:

• Solid State Chemistry
• Materials Science
• Condensed Matter Physics

Background:

• Iridium germanides are of interest for their unique structural and electronic properties.
• Understanding the crystal structure and physical properties of novel intermetallic compounds is crucial for materials discovery.

Purpose of the Study:

• To synthesize and characterize polycrystalline Iridium Germanide (IrGe4).
• To determine the crystal structure and investigate the electronic and magnetic properties of IrGe4.
• To explore the potential for topological electronic states in IrGe4.

Main Methods:

• Synthesis via high-temperature annealing of elements.
• Compositional analysis using energy-dispersive X-ray spectroscopy.
• Crystal structure determination using convergent-beam electron diffraction and Rietveld refinements with synchrotron powder X-ray diffraction data.
• Electrical resistivity and Hall effect measurements.
• Density functional theory (DFT) calculations for electronic band structure.

Main Results:

• Polycrystalline IrGe4 was successfully synthesized and confirmed.
• The material crystallizes in a chiral structure (space group P3121), distinct from a polar structure.
• Temperature-dependent resistivity shows metallic behavior.
• Nonsaturating magnetoresistance reaching 11.5% at 9 T and 10 K was observed.
• Hall resistivity indicates holes as majority carriers (4.02 × 10^21 cm^-3 at 300 K).
• DFT calculations reveal a Weyl point above the Fermi level with a chiral charge of +3.

Conclusions:

• IrGe4 possesses a chiral crystal structure with potential topological electronic properties.
• The observed metallic behavior and significant magnetoresistance highlight its potential for electronic device applications.
• The predicted Weyl point suggests further investigation into its topological quantum phenomena is warranted.