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A chiral fermionic valve driven by quantum geometry.
Anvesh Dixit1, Pranava K Sivakumar1, Kaustuv Manna2,3
1Max Planck Institute of Microstructure Physics, Halle (Saale), Germany.
Nature
|December 31, 2025
Summary
Researchers developed a chiral fermionic valve using quantum geometry to separate particles by chirality without magnetic fields. This breakthrough enables controllable quantum interference and current-induced magnetization.
Area of Science:
- Condensed Matter Physics
- Quantum Materials
- Topological Matter
Background:
- Topological semimetals feature fermions with opposite chiralities.
- Chiral transport typically requires magnetic fields or dopants to separate chiral states.
- Existing methods struggle to isolate and control chiral fermions effectively.
Purpose of the Study:
- To utilize quantum geometry for filtering fermions by chirality.
- To demonstrate real-space separation of opposite chiral currents without magnetic fields.
- To establish a chiral fermionic valve with novel functionalities.
Main Methods:
- Fabrication of devices from single-crystal PdGa in a three-arm geometry.
- Exploitation of quantum geometry to induce anomalous velocities in chiral fermions.
- Observation of quantum interference of spatially separated chiral currents.
Main Results:
- Demonstrated real-space separation of currents with opposite fermionic chiralities.
- Observed quantum interference of these currents in the absence of magnetic fields.
- Exhibited a nonlinear Hall effect due to quantum-geometry-induced anomalous velocities.
Conclusions:
- The developed chiral fermionic valve spatially separates fermions by Chern number using quantum geometry.
- The device enables tunable current-induced magnetization.
- It provides a platform for controllable quantum interference of chiral quasiparticles.
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