Magnetophotoluminescence of positively-charged excitons in GaAs quantum wells

We have studied the low-temperature photoluminescence of high-mobility two-dimensional hole gases in GaAs quantum wells in magnetic fields up to View the MathML source. We have observed both spin states of the neutral (X0) and of the singlet state of the positively charged exciton (X+), allowing us to determine their g-factors and the binding energy of X+. We find that the g-factor of the X+ is larger than that of X0 by a factor of 1.6. In very high fields, we expect the low-energy spin-state of X+ to be bound only because of the Zeeman interaction.