Band modification in (Ga, Mn)As evidenced by new measurement scheme --- magnetic photoresistance circular dichroism

TL;DR

This paper introduces a new measurement scheme called magnetic photoresistance circular dichroism (PR-MCD) to conclusively demonstrate that exchange interactions modify the band structure in (Ga, Mn)As, revealing new insights into diluted magnetic semiconductors.

Contribution

The paper develops and applies a novel PR-MCD technique to provide unambiguous evidence of band modification by exchange interactions in (Ga, Mn)As.

Findings

PR-MCD detects MO effects solely from interband transitions.

Evidence confirms exchange interactions modify the host band structure.

Spectra reveal features possibly due to strong coupling at high Mn concentrations.

Abstract

The expected features of diluted magnetic semiconductors still remain in controversial issue, concerning whether or not s, p-d (f) exchange interactions indeed modify the host semiconductor band structure. To solve this doubt, a new scheme for measuring magneto-optical (MO) effect is developed, called magnetic photoresistance circular dichroism (PR-MCD), which detects the differential photoresistance of materials between two circularly polarized excitations. That allows us to detect the MO effect induced only by interband transitions, and provide unambiguous evidence that the host semiconductor band structure is indeed modified by the strong exchange interactions. Our PR-MCD spectra also disclose intrigue features which may come from strong coupling correlation effect at very high manganese concentration limit.