Magneto-resistance quantum oscillations in a magnetic two-dimensional electron gas

TL;DR

This study investigates magneto-transport properties of two-dimensional electron gases in magnetic quantum wells, revealing unique oscillation patterns and magnetic interactions influenced by Mn ions and temperature effects.

Contribution

It introduces a modified Lifshitz-Kosevich formalism to describe SdH oscillations in magnetic 2DEGs, highlighting Mn clustering and temperature-dependent Landau level broadening.

Findings

Characteristic beating pattern in SdH oscillations due to electron-Mn exchange

Formation of Mn clusters with anti-ferromagnetic interactions

Unusual decrease in Landau level broadening with temperature

Abstract

Magneto-transport measurements of Shubnikov-de Haas (SdH) oscillations have been performed on two-dimensional electron gases (2DEGs) confined in CdTe and CdMnTe quantum wells. The quantum oscillations in CdMnTe, where the 2DEG interacts with magnetic Mn ions, can be described by incorporating the electron-Mn exchange interaction into the traditional Lifshitz-Kosevich formalism. The modified spin splitting leads to characteristic beating pattern in the SdH oscillations, the study of which indicates the formation of Mn clusters resulting in direct anti-ferromagnetic Mn-Mn interaction. The Landau level broadening in this system shows a peculiar decrease with increasing temperature, which could be related to statistical fluctuations of the Mn concentration.