Two-Parameter Scaling of Microwave Rectification vs Microwave Power at the Boundary between Two-Dimensional Electron Systems

TL;DR

This study investigates microwave rectification at the boundary of two-dimensional electron systems, revealing a universal scaling law of rectified voltage with microwave power and proposing a thermoelectric theory for the observed behavior.

Contribution

It introduces a two-parameter scaling law for microwave rectification and develops a thermoelectric model that matches experimental results.

Findings

Rectified voltage scales universally with microwave power above 4 GHz.

Voltage is linear at low power and follows a square root dependence at higher power.

Thermoelectric response due to local overheating explains the rectification behavior.

Abstract

We report measurements of the rectification of microwave radiation (0.7-20 GHz) at the boundary between two-dimensional electron systems separated by a narrow gap on a silicon surface for different temperatures, electron densities and microwave power. For frequencies above 4 GHz and different temperatures, the rectified voltage V_{dc} as a function of microwave power P can be scaled onto a single universal curve V*_{dc}=f*(P*). The scaled voltage is a linear function of power, V*_{dc} ~ P* for small power and proportional to P*^{1/2} at higher power. A theory is proposed that attributes the rectification to the thermoelectric response due to strong local overheating by the microwave radiation at the boundary between two dissimilar 2D metals. Excellent agreement is obtained between theory and experiment.