Complex dielectric constant of Cd_0.8SMn_0.2Te crystals near the fundamental absorption edge

Abstract

The complex dielectric constant of Cd0.8Mn0.2Te single crystals is determined from reflection measurements in the photon energy range from 1.75 to 2 eV at the lattice temperature T = 2 K. The light reflection model includes exciton absorption and dispersive background dielectric constant contribution. The same model is found to be efficient in describing the band of nonreciprocal reflection arising in nonzero magnetic field in the Voigt geometry.

Surface-fracture-related photoluminescence of CdMnTe crystals

“…The enhanced light emission and absorption by the fractured surface and particularly unexpected bright 1 OA peak position for Cd 0.8 Mn 0.2 Te, as shown in Fig. 4, has been determined in earlier experiments [31]. photoluminescence observed on the dark side of Cd 0.8 Mn 0.2 Te crystals are encouraging features for experimental research continuation aiming at a more controllable technology.…”

“…2). The crystallite PL peak positions are red-shifted relative to the peak of fundamental absorption (being at 1.91 eV for this particular Mn mole fraction x = 0.2 [31]).…”

“…1with the values of n(E) and κ(E) for Cd 0.8 Mn 0.2 Te as given by the complex dielectric function ε(E) deduced from reflectivity measurements in Ref. [31], supposing the effective temperature to be T ef = 400 K. The adjustable effective temperature is conventionally attributed to the light-emitting ensemble (exci-tons, electron-hole gas, etc. ); therefore, it is set high compared to the crystal lattice temperature.…”

“…We take again the complex dielectric function ε(E) of Cd 0.8 Mn 0.2 Te as deduced from reflectivity measurements in Ref. [31] keeping the background component independent of whether the crystal is in normal or in excited state and inverting sign (when modelling emission) of the component of inter-band transitions. This model gives the PL line shape and peak position in good agreement with the experiment (Fig.…”

Photonic Crystal Architecture for Room-Temperature Equilibrium Bose-Einstein Condensation of Exciton Polaritons

“…The spectrum and wavefunction of the photonic bands are calculated by solving the Maxwell equations using the plane wave expansion method [60]. In calculating the photonic bands in Cd 0.4 Mg 0.6 Te/Cd 0.8 Mn 0.2 Te Fabry-Pérot cavity the dielectric constants for Cd 0.4 Mg 0.6 Te is 7.0 (linear interpolation between the dielectric constant of CdTe, 8.5 [49], and that of MgTe, 6.0 [50]) while the dielectric constant of Cd 0.8 Mn 0.2 Te is 7.8 [74]. The electronic structures are calculated using the effective mass approximation [45].…”