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Updated: Sep 13, 2025
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Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
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Fluctuations and Correlations of Local Topological Order Parameters in Disordered Two-Dimensional Topological
Roberta Favata1, Nicolas Baù1, Antimo Marrazzo2
1Università di Trieste, Dipartimento di Fisica, I-34151 Trieste, Italy.
Physical Review Letters
|July 31, 2025
Summary
Disorder can destroy topological insulators but also create them. New local markers reveal how fluctuations drive these topological phase transitions in 2D materials.
Area of Science:
- Condensed matter physics
- Materials science
Background:
- Two-dimensional topological insulators possess insulating bulk and conductive edge states.
- Disorder can destroy topological phases via Anderson localization or induce topological Anderson insulators.
Purpose of the Study:
- To investigate disorder-driven topological phase transitions using space-resolved topological markers.
- To analyze the role of fluctuations and correlations in local topology under disorder.
Main Methods:
- Numerical simulations of the Haldane and Kane-Mele models with Anderson disorder and vacancies.
- Utilized supercells with open and periodic boundary conditions.
- Developed space-resolved topological markers as local order parameters.
Main Results:
- Short-scale topological fluctuations vanish upon coarse graining, except at phase transitions.
- Correlation length of topological markers peaks at phase transitions, showing large-scale fluctuations.
- Identified critical exponents of the topological correlation function, appearing universal across disorder types.
Conclusions:
- Space-resolved topological markers effectively probe local topology and disorder effects.
- These markers can distinguish between different topological phase transitions.
- The study provides a new perspective on understanding topological phases under disorder.
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