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Short--range impurity in the vicinity of a saddle point and the levitation of the 2D delocalized states in a magnetic field

A. Gramada·M. E. Raikh
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Abstract

The effect of a short--range impurity on the transmission through a saddle--point potential for an electron, moving in a strong magnetic field, is studied. It is demonstrated that for a random position of an impurity and random sign of its potential the impurity--induced mixing of the Landau levels diminishes {\em on average} the transmission coefficient. This results in an upward shift (levitation) of the energy position of the delocalized state in a smooth potential. The magnitude of the shift is estimated. It increases with decreasing magnetic field $B$ as $B^{-4}$.

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A. Gramada, M. E. Raikh. 1996-01-08. Short--range impurity in the vicinity of a saddle point and the levitation of the 2D delocalized states in a magnetic field. https://doi.org/10.1103/physrevb.54.1928

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