Dynamical Kohn Anomaly in Surface Acoustic Wave Response in Quantum Hall Systems Near $\nu = 1/2$

TL;DR

This paper demonstrates a dynamical Kohn Anomaly in surface acoustic wave responses near filling factor 1/2 in Quantum Hall systems, showing enhanced effects under periodic modulation that are experimentally observable.

Contribution

It introduces the dynamical analog of the Kohn Anomaly in Quantum Hall systems and predicts observable effects in surface acoustic wave responses near $ u=1/2$.

Findings

Kinks in velocity shift and attenuation coefficient are identified.

Effects are significantly enhanced with periodic modulation.

The phenomena are predicted to be observable experimentally.

Abstract

The dynamical analog of the Kohn Anomaly image of the Fermi Surface is demonstrated for the response functions to the surface acoustic waves in Quantum Hall Systems near $\nu = 1/2$. Kinks appear in the velocity shift $Delta s/s$ and attenuation coefficient $\Gamma$. The effect is considerably enhanced under periodic modulation and should be observable.