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Non-reciprocal Coulomb drag between Chern insulators
Yu Fu1,2,3, Yu Huang1,2,3, Qing Lin He4,5,6
1International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China.
Nature Communications
|March 29, 2025
Summary
We observed non-reciprocal Coulomb drag in ferromagnetic topological insulators, violating Onsager
Area of Science:
- Condensed Matter Physics
- Topological Materials
- Quantum Phenomena
Background:
- Coulomb drag, the induction of voltage in one conductor by current in another, is typically reciprocal.
- This effect is well-understood in nonmagnetic systems, adhering to Onsager's reciprocity.
- Previous studies focused on nonmagnetic, strongly interacting systems.
Purpose of the Study:
- To investigate Coulomb drag in magnetic topological insulators.
- To explore the possibility of non-reciprocal Coulomb drag.
- To understand the underlying mechanisms in these novel systems.
Main Methods:
- Experimental measurements of Coulomb drag between two ferromagnetic Chern insulators.
- Utilized current and circuit reversals to detect non-reciprocity.
- Analyzed nonlinear current-voltage characteristics and temperature dependence.
Main Results:
- Observed strong non-reciprocal Coulomb drag signals in both longitudinal and transverse directions.
- These signals violate Onsager's reciprocity and appear in the multidomain state of Chern insulators.
- Drag is linked to rectification of mesoscopic fluctuations, quantum shot noise, and magnetic dynamics.
Conclusions:
- Demonstrated non-reciprocal Coulomb drag in magnetic topological systems for the first time.
- Highlights the crucial role of magnetic dynamics and multidomain states.
- Expands the study of Coulomb drag into the domain of topological magnetism.
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