Circularly polarized light detector based on ferromagnet/semiconductor junctions

TL;DR

This paper demonstrates a ferromagnet/semiconductor junction device that detects circularly polarized light through helicity-dependent photocurrent, showing temperature-dependent behavior and potential room-temperature operation.

Contribution

It introduces a novel ferromagnet/semiconductor junction for helicity-dependent photocurrent detection with measurable room-temperature response.

Findings

Helicity-dependent photocurrent detected with a hysteresis loop.

Photocurrent magnitude of approximately 0.2 nA at 5 K.

Relative delta-I maximized at 125-150 K and measurable at room temperature.

Abstract

Helicity-dependent photocurrent delta-I has been detected successfully under experimental configuration that a circularly polarized light beam is impinged with a right angle on a cleaved sidewall of the Fe/x-AlOx/GaAs-based n-i-p double-heterostructure. The photocurrent delta-I has showed a well-defined hysteresis loop which resembles that of the magnetization of the in-plane magnetized Fe layer in the devices. The value of delta-I has been |delta-I|~0.2 nA at 5 K under the remnant magnetization state. Study on temperature dependence of the relative delta-I value at H = 0 has revealed that it is maximized at temperatures 125 - 150 K, and is still measurable at room temperature.