Photoluminescence of p-doped quantum wells with strong spin splitting

Abstract

The spectroscopic properties of a spin polarized two-dimensional hole gas are studied in modulation doped (Cd,Mn)Te quantum wells. The giant Zeeman effect induces a significant spin splitting even at very small values of the applied field. Several methods of measuring the carrier density (Hall effect, filling factors of the Landau levels at high field, various manifestations of Moss-Burstein shifts) are described and calibrated. The value of the spin splitting needed to fully polarize the hole gas, evidences a strong enhancement of the spin susceptibility of the hole gas due to carrier-carrier interaction. At small values of the spin splitting, whatever the carrier density (non zero) is, photoluminescence lines are due to the formation of charged excitons in the singlet state. Spectral shifts in photoluminescence and in transmission (including an "excitonic Moss-Bustein shift") are observed and discussed in terms of excitations of the partially or fully polarized hole gas. At large spin splitting, and without changing the carrier density, the singlet state of the charged exciton is destabilized in favour of a triplet state configuration of holes. The binding energy of the singlet state is thus measured and found to be independent of the carrier density (in contrast with the splitting between the charged exciton and the neutral exciton lines). The state stable at large spin splitting is close to the neutral exciton at low carrier density, and close to an uncorrelated electron-hole pair at the largest values of the carrier density achieved. The triplet state gives rise to a characteristic double-line structure with an indirect transition to the ground state (with a strong phonon replica) and a direct transition to an excited state of the hole gas.

References in corpus (9)

• Light and electric field control of ferromagnetism in magnetic quantum structures
• Spin Susceptibility of an Ultra-Low Density Two Dimensional Electron System
• Excitons and charged excitons in semiconductor quantum wells
• Binding Energy of Charged Excitons in ZnSe-based Quantum Wells
• Magnetic field dependence of the energy of negatively charged excitons in semiconductor quantum wells
• Optical Method for Determination of Carrier Density in Modulation Doped Quantum Wells
• p-Type doping of II-VI heterostructures from surface states: application to ferromagnetic Cd${}_{1-x}$Mn${}_x$Te quantum wells
• Stability of trions in strongly spin-polarized two-dimensional electron gases
• Hole-hole correlation effects on magnetic properties of Mn${}_x$III${}_{1-x}$V diluted magnetic semiconductors

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• Ferromagnetic properties of p-(Cd,Mn)Te quantum wells: Interpretation of magneto-optical measurements by Monte Carlo simulations
• Angle-resolved optically detected magnetic resonance as a tool for strain determination in nanostructures
• Magnetic ion relaxation time distribution within a quantum well
• Carrier localization in defected areas of (Cd, Mn)Te quantum well investigated via Optically Detected Magnetic Resonance employed in the microscale