# Collective excitations in a magnetically doped quantized Hall ferromagnet

## TL;DR

This paper develops a theoretical framework for understanding collective excitations in a magnetically doped quantum Hall ferromagnet, revealing how impurity interactions influence spin states and potential phase transitions in 2DEG systems.

## Contribution

It introduces a novel theory describing collective states and impurity effects in magnetically doped quantum Hall systems, including conditions for new spin textures and phase transitions.

## Key findings

- Bound and delocalized spin-excitons spectrum analyzed
- Renormalization of impurity Zeeman splitting due to exchange interaction
- Impurity-related transitions to new ground state phases possible

## Abstract

A theory of collective states in a magnetically quantized two-dimensional electron gas (2DEG) with half-filled Landau level (quantized Hall ferromagnet) in the presence of magnetic 3d impurities is developed. The spectrum of bound and delocalized spin-excitons as well as the renormalization of Zeeman splitting of the impurity 3d levels due to the indirect exchange interaction with the 2DEG are studied for the specific case of n-type GaAs doped with Mn where the Lande` g-factors of impurity and 2DEG have opposite signs. If the sign of the 2DEG g-factor is changed due to external influences, then impurity related transitions to new ground state phases, presenting various spin-flip and skyrmion-like textures, are possible. Conditions for existence of these phases are discussed. PACS: 73.43.Lp, 73.21.Fg, 72.15.Rn