Universal Conductance Fluctuations in a MnBi₂Te₄ Thin Film

Area of Science:

• Condensed Matter Physics
• Quantum Materials Science
• Spintronics

Background:

• Quantum coherence in mesoscopic conductors leads to unique transport phenomena.
• Magnetic order significantly influences electron transport, but its interplay with coherence is understudied.
• Topological materials offer a unique platform to investigate fundamental quantum phenomena.

Purpose of the Study:

• To investigate quantum coherence-driven universal conductance fluctuations in different magnetic phases of MnBi2Te4.
• To explore the relationship between magnetic order, quantum coherence, and electron transport.
• To understand the influence of magnetic domain wall dynamics on transport properties.

Main Methods:

• Utilized conductance fluctuation measurements in thin films of the topological material MnBi2Te4.
• Analyzed magnetotransport data across antiferromagnetic, canted antiferromagnetic, and ferromagnetic phases.
• Extracted charge carrier phase coherence length and conductance magnetofingerprints.

Main Results:

• A charge carrier phase coherence length of approximately 100 nm was observed across all magnetic phases.
• Conductance magnetofingerprints were repeatable within each magnetic phase.
• A surprising dependence of the magnetofingerprint on field sweep direction was found in antiferromagnetic and canted antiferromagnetic phases, but not the ferromagnetic phase.

Conclusions:

• Quantum coherence effects are present and measurable across different magnetic phases of MnBi2Te4.
• Conductance fluctuation measurements are sensitive to magnetic domain wall motion and nucleation.
• The findings provide insights into the complex interplay of magnetism and quantum transport in topological materials.