Tuning gaps and phases of a two-subband system in a quantizing magnetic field
Abstract
In this work we study the properties of a two-subband quasi-two-dimensional electron system in a strong magnetic field when the electron filling factor is equal to four. When the cyclotron energy is close to the intersubband splitting the system can be mapped onto a four-level electron system with an effective filling factor of two. The ground state is either a ferromagnetic state or a spin-singlet state, depending on the values of the inter-level splitting and Zeeman energy. The boundaries between these phases are strongly influenced by the inter-electron interaction. A significant exchange-mediated enhancement of the excitation gap results in the suppression of the electron-phonon interaction. The rate of absorption of non-equilibrium phonons is calculated as a function of Zeeman energy and inter-subband splitting. The phonon absorption rate has two peaks as a function of intersubband splitting and has a step-like structure as a function of Zeeman energy.
Keywords
Cite
@article{arxiv.cond-mat/0111378,
title = {Tuning gaps and phases of a two-subband system in a quantizing magnetic field},
author = {V. M. Apalkov and M. E. Portnoi},
journal= {arXiv preprint arXiv:cond-mat/0111378},
year = {2009}
}