arXiv subjects

G. M. Jacobsen

Publications and source records attributed to G. M. Jacobsen.

4 recordsLinked to original sources

arXiv2026

Effect of electric current on optical response of viscous electron-hole plasma

The influence of the Hall voltage on the photoluminescence of a dense hydrodynamic electron-hole plasma laser generated in a mesoscopic n-doped GaAs channel under intense laser excitation is studied. Laser excitation induces an interband current determined by the recombination of photogenerated electron-hole pairs. As a result, background electrons drifting under the influence of the Hall voltage form an effective Hall current. The Coulomb drag caused by the Hall current causes the accumulation of light holes, leading to the appearance of a double photoluminescence line formed by the recombination of excitons and trions. In contrast, in the absence of a Hall current, the shift in the photoluminescence energy associated with heavy holes occurs due to the electric field created by the Hall potential difference.

cond-mat.mes-hall↗

arXiv2025

Current-induced Magnetoexcitons in Mesoscopic Electron-hole Plasma

A radical restructuring of the optical response of highly excited electron-hole plasma formed in a mesoscopic GaAs/AlGaAs channel in a quantizing magnetic field when an electric current flows in the channel has been discovered. In the absence of current, the emission spectra are caused by transitions between Landau levels formed in the conduction band and in the valence band of heavy holes. A critical electric current leads to a drastic change in the emission spectra with a predominant contribution from light holes. It is shown that the current causes local accumulation of light holes due to Coulomb drag, which leads to strong electron-hole coupling and, as a consequence, the formation of excitons and trions.

cond-mat.mes-hall↗

arXiv2024

Hydrodynamics of electron-hole fluid photogenerated in a mesoscopic two-dimensional channel

The dynamics of the diffusion flow of holes photoinjected into a mesoscopic GaAs channel of variable width, where they, together with background electrons, form a hydrodynamic electron-hole fluid, is studied using time-resolved microphotoluminescence. It is found that the rate of recombination of photoinjected holes, which is proportional to the rate of their flow, decreases when holes pass through the expanded sections of the channel. In fact, this is the Venturi effect, which consists in a decrease in the velocity of the fluid in the expanded sections of the pipe. Moreover, a non-uniform diffusion velocity profile is observed, similar to the parabolic Hagen-Poiseuille velocity profile, which indicates a viscous hydrodynamic flow. It is shown that in argeement with a theory, the magnetic field strongly suppresses the viscosity of the electron-hole fluid. Additional evidence of the viscous nature of the studied electron-hole fluid is the observed increase in the recombination rate with increasing temperature, which is similar to the decrease in the electrical resistance of viscous electrons with temperature.

cond-mat.mes-hall↗

arXiv2022

Spin dependent analysis of homogeneous and inhomogeneous exciton decoherence in magnetic fields

This paper discusses the combined effects of optical excitation power, interface roughness, lattice temperature, and applied magnetic fields on the spin-coherence of excitonic states in GaAs/AlGaAs multiple quantum wells. For low optical powers, at lattice temperatures between 4 K and 50 K, the scattering with acoustic phonons and short-range interactions appear as the main decoherence mechanisms. Statistical fluctuations of the band-gap however become also relevant in this regime and we were able to deconvolute them from the decoherence contributions. The circularly polarized magneto-photoluminescence unveils a non-monotonic tuning of the coherence for one of the spin components at low magnetic fields. This effect has been ascribed to the competition between short-range interactions and spin-flip scattering, modulated by the momentum relaxation time.

cond-mat.mes-hall↗