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Universal Conductance Fluctuations in Quantum Anomalous Hall Insulators.
Peng Deng1,2, Peng Zhang3, Gang Qiu4
1Beijing Academy of Quantum Information Sciences, Beijing, China.
Advanced Materials (Deerfield Beach, Fla.)
|December 29, 2025
Summary
Universal conductance fluctuations (UCF) were observed in magnetic topological insulator films within the quantum anomalous Hall (QAH) regime. These findings reveal distinct interference processes in bulk and edge states, offering new insights into QAH system transport.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Phenomena
Background:
- Universal conductance fluctuations (UCF) are a key mesoscopic transport phenomenon in disordered systems.
- UCF are fundamentally linked to phase coherent transport and influence low-temperature properties.
- Topological insulators (TIs) exhibit unique electronic properties, including the quantum anomalous Hall (QAH) effect.
Purpose of the Study:
- To investigate UCF in magnetically doped TI thin films operating in the QAH regime.
- To characterize the nature and origin of conductance fluctuations in mesoscopic QAH devices.
- To explore quantum interference phenomena in QAH insulators.
Main Methods:
- Fabrication of mesoscopic QAH devices using magnetically doped TI thin films.
- Measurement of electrical conductance as a function of magnetic field and temperature.
- Analysis of conductance fluctuations to identify distinct components and their dependencies.
Main Results:
- Observation of aperiodic yet reproducible conductance fluctuations in mesoscopic QAH devices.
- Fluctuations demonstrated robustness against changes in field sweeping direction and temperature.
- Two distinct fluctuation components were identified with differing temperature dependencies, linked to bulk and edge states.
Conclusions:
- UCF phenomena are present and significant in magnetically doped TI thin films within the QAH regime.
- Contrasting temperature dependencies of fluctuation components provide evidence for distinct interference mechanisms in bulk and edge states.
- These findings enhance the understanding of mesoscopic transport and quantum interference in QAH systems.
Keywords:
magnetic topological insulatorsmolecular beam epitaxyquantum anomalous hall effectquantum interferenceuniversal conductance fluctuationsMore Related Videos
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