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arXiv · 2601.05064

Electrically Controllable Flat Band in Two-Dimensional Electron Gases under Nonuniform Magnetic Fields

You-Ting Huang·Chao-Cheng Kaun·Ching-Hao Chang
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Abstract

Flat bands underlie a diverse range of quantum phenomena, from strongly correlated phases to superconductivity. We theoretically establish that a two-dimensional electron gas under a linear magnetic-field gradient and a transverse electric field exhibits electrically tunable flat bands. When the electric field magnitude is tuned to a value within a discrete sequence, these bands become strictly dispersionless. By providing exact classical and quantum solutions, we demonstrate that these states are high-order Landau levels associated with drift-compensated cyclotron orbits of carriers arising from the synergy between the magnetic-field gradient and the electric field. These electrically controllable Landau levels exhibit quantized Hall conductance and a strongly enhanced density of states. Our results provide a new route for flat-band creation, magnetoelectric band engineering, and quantized Hall currents controlled via source-drain voltage.

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You-Ting Huang, Chao-Cheng Kaun, Ching-Hao Chang. 2026-01-08. Electrically Controllable Flat Band in Two-Dimensional Electron Gases under Nonuniform Magnetic Fields. https://arxiv.org/abs/2601.05064

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