Smearing of the 2D Kohn anomaly in a nonquantizing magnetic field: Implications for the interaction effects

TL;DR

This paper investigates how a weak magnetic field affects the electron lifetime and density of states in a 2D electron gas, revealing that magnetic field-induced smearing of the Kohn anomaly influences interaction effects even at high temperatures.

Contribution

It demonstrates the sensitivity of thermodynamic and transport properties to weak magnetic fields due to smearing of the Kohn anomaly caused by curved electron trajectories.

Findings

Electron lifetime is affected by magnetic field-induced smearing.

Tunnel density of states shows sensitivity to magnetic field.

Quantum oscillations are washed out at high temperatures.

Abstract

Thermodynamic and transport characteristics of a clean two-dimensional interacting electron gas are shown to be sensitive to the weak perpendicular magnetic field even at temperatures much higher than the cyclotron energy, when the quantum oscillations are completely washed out. We demonstrate this sensitivity for two interaction-related characteristics: electron lifetime and the tunnel density of states. The origin of the sensitivity is traced to the field-induced smearing of the Kohn anomaly; this smearing is the result of curving of the semiclassical electron trajectories in magnetic field.