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arXiv · 2207.10066

Breathing mode in open-orbit magnetotransport: a magnetic lens with a quantum mechanical focal length

D. O. Oriekhov·T. T. Osterholt·T. Vakhtel·A. R. Akhmerov·C. W. J. Beenakker
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Abstract

We consider the propagation of electrons in a lattice with an anisotropic dispersion in the $x$--$y$ plane (lattice constant $a$), such that it supports open orbits along the $x$-axis in an out-of-plane magnetic field $B$. We show that a point source excites a "breathing mode", a state that periodically spreads out and refocuses after having propagated over a distance $\ell =(eaB/h)^{-1}$ in the $x$-direction. Unlike known magnetic focusing effects, governed by the classical cyclotron radius, this is an intrinsically quantum mechanical effect with a focal length $\propto\hbar$.

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D. O. Oriekhov, T. T. Osterholt, T. Vakhtel, A. R. Akhmerov, C. W. J. Beenakker. 2022-07-20. Breathing mode in open-orbit magnetotransport: a magnetic lens with a quantum mechanical focal length. https://doi.org/10.1103/physrevb.106.235413

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