Fig. 2
Polarization spectroscopy in the cw regime. a PL spectra at U = 0 (red) and −1 V (blue). b Magnetic field dependences of the circular polarization degree \(\rho _{\mathrm{c}}^{\mathrm{\pi }}\left( {B_{\mathrm{F}}} \right)\) measured at U = 0 V, ħωPL = 1.598 eV (red squares), U = −1 V, ħωPL = 1.594 eV (blue circles), and U = 0, ħωPL = 1.610 eV (red stars), using linearly polarized excitation. The arrow indicates the amplitude Aπ(0 V) of the FM proximity effect for U = 0 at 1.598 eV detection energy. c Spectral dependences of \(\rho _{\mathrm{c}}^{\mathrm{\pi }}\) for U = 0 V and −1 V. d Amplitude Aπ(U) of the FM proximity effect (red circles) and the energy of the PL peak ħωmax(U) (blue circles) as functions of the gate voltage. The red curve is a fit using Eq. (8) with A = 2.2%, U0 = 0.8 V, and U1 = 1.8 V. Excitation was done with photon energy 1.691 eV (below the band gap of the (Cd,Mg)Te barriers) using a power density of 4 W cm−2. In all cases the magnetic field was BF = −220 mT (except of (b)) and temperature T = 2 K. Error bars represent standard deviations
