The effective electron $g$ factor, $g_{\text{eff}}$, is measured in a two-dimensional electron gas (2DEG) in modulation-doped ZnSe- and CdTe-based quantum wells by means of time-resolved pump-probe Kerr rotation. The measurements are performed in magnetic fields applied in the Voigt geometry, i.e., normal to the optical axis parallel to the quantum well plane, in the field range $0.05–6$ T at temperatures $1.8–50\mathrm{K}$. The $g_{\text{eff}}$ absolute value considerably increases with increasing electron density $n_e$. $g_{\text{eff}}$ changes in the ZnSe-based QWs from $+1.1$ to $+1.9$ in the $n_e$ range $3\times {10}^{10}-1.4\times {10}^{12}{\mathrm{cm}}^{-2}$ and in the CdTe-based QWs from $-1.55$ down to $-1.76$ in the $n_e$ range $5\times {10}^9-3\times {10}^{11}{\mathrm{cm}}^{-2}$. The modification of $g_{\text{eff}}$ reduces with increasing magnetic field, increasing temperature of lattice and 2DEG, the latter achieved by a higher photoexcitation density. A theoretical model is developed that considers the renormalization of the spin-orbit coupling constant of the two-dimensional electrons by the electron-electron interaction and takes into account corrections to the electron-electron interaction in the Hubbard form. The model results are in good agreement with experimental data.

• Received 24 July 2020
• Revised 27 August 2020
• Accepted 28 August 2020

DOI:https://doi.org/10.1103/PhysRevB.102.125306