Nonlinear Optical studies of the Transient Coherence in the Quantum Hall System
arXiv:cond-mat/0607550 · doi:10.1016/j.ssc.2006.05.051
Abstract
We review recent investigations of the femtosecond non-linear optical response of the two-dimensional electron gas (2DEG) in a strong magnetic field. We probe the Quantum Hall (QH) regime for filling factors . Our focus is on the transient coherence induced via optical excitation and on its time evolution during early femtosecond timescales. We simultaneously study the interband and intraband coherence in this system by using a nonlinear spectroscopic technique, transient three-pulse four wave mixing optical spectroscopy, and a many-body theory. We observe striking differences in the temporal and spectral profile of the nonlinear optical signal between a modulation doped quantum well system (with the 2DEG) and a similar undoped quantum well (without a 2DEG). We attribute these qualitative differences to Coulomb correlations between the photoexcited electron-hole pairs and the 2DEG. We show, in particular, that intraband many-particle coherences assisted by the inter-Landau-level magnetoplasmon excitations of the 2DEG dominate the femtosecond nonlinear optical responce. The most striking effect of these exciton-magnetoplasmon coherences is a large off-resonant four-wave-mixing signal in the case of very low photoexcited carrier densities, not observed in the undoped system, with strong temporal oscillations and unusually symmetric temporal profile.
22 pages, 9 figures; review article to be published in Solid State Communications
References in corpus (9)
- Theory of exciton-exciton correlation in nonlinear optical response
- Coherence Network in the Quantum Hall Bilayer
- Splitting of Long-Wavelength Modes of the Fractional Quantum Hall Liquid at
- Many-body Correlation Effects in the Ultrafast Nonlinear Optical Response of Confined Fermi Seas
- Ultrafast Nonlinear Optical Response of Strongly Correlated Systems: Dynamics in the Quantum Hall Effect Regime
- Ultrafast Coulomb-induced dynamics of 2D magnetoexcitons
- Three--body Correlation Effects on the Spin Dynamics of Double--Exchange Ferromagnets
- Theory of ultrafast exciton dynamics in the Quantum Hall system
- Three-body correlations in the Nagaoka state on the square lattice