Hidden Density-Wave Instability in the Trimer Ruthenate Ba_{4}Ru_{3}O_{10}

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Ba_{4}Ru_{3}O_{10} was considered a purely antiferromagnetic insulator.
• Ruthenates are known for complex electronic behaviors due to strong electron correlations.

Purpose of the Study:

• To investigate the electronic properties of Ba_{4}Ru_{3}O_{10}.
• To characterize the nature of the observed anomalies in Ba_{4}Ru_{3}O_{10}.

Main Methods:

• Transport measurements
• Thermodynamic measurements
• Structural analysis
• Magnetic field response studies
• Substitution studies (Ir for Ru)

Main Results:

• An unprecedented two-stage density-wave instability was found in Ba_{4}Ru_{3}O_{10}.
• The first stage at 100 K shows electronic reconstruction with anomalies insensitive to magnetic fields up to 14 T.
• The second stage below 20 K exhibits strongly nonlinear transport, including depinning thresholds and negative differential resistance.

Conclusions:

• Ba_{4}Ru_{3}O_{10} hosts a hidden density-wave instability intertwined with antiferromagnetism.
• This instability involves a strongly pinned collective electronic mode, challenging previous understanding.
• The material is a rare example of a correlated system with such unique electronic phenomena.