Faraday-rotation spectra of semimagnetic semiconductors

Optical and magnetooptical study of CdTe crystals doped with rare earth ions

“…Therefore, in the considered case we can conclude of exhibition of strong spin exchange interaction between the f electrons of Dy ions and s, p band carriers (electrons and holes). In particular, reversal of the direction of the Faraday rotation in its spectral dependence is associated with a positive part and negative part due to pure Zeeman and s, p-f spin exchange interaction according to several theoretical models [8][9][10][11][12] which have been developed for case of the sp-d exchange interaction. First analysis of the Faraday rotation spectra for semimagnetic semiconductors [8] was made on the base of a single-oscillator model for the refractive index that involves the interband excitonic transition at the fundamental gap E g .…”

“…However, both oscillator models could not provide direct connection with microscopic origin of the Zeeman effect responsible for the Faraday effect. These drawbacks were taken into account in microscopic model [11,12] where an analytical expression of the Verdet constant of semimagnetic semiconductors was derived from a microscopic analysis of the transverse susceptibility responsible for the Faraday effect. The theory [12] explained experimental results on Faraday rotation spectra in Cd 1−x Mn x Te and Zn 1−x Mn x Te crystals by using only two (normalization and exchange interaction) parameters.…”

“…These drawbacks were taken into account in microscopic model [11,12] where an analytical expression of the Verdet constant of semimagnetic semiconductors was derived from a microscopic analysis of the transverse susceptibility responsible for the Faraday effect. The theory [12] explained experimental results on Faraday rotation spectra in Cd 1−x Mn x Te and Zn 1−x Mn x Te crystals by using only two (normalization and exchange interaction) parameters. Besides, recent experimental results on Faraday rotation in Cd 1−x Gd x Te solid solutions [4] which include rare earth element Gd were interpreted in term of a microscopic model.…”

Giant Faraday Rotation in CdTe Spin-Doped with Rare Earth Ions

“…In particular, reversal of the direction of the Faraday rotation in its spectral dependence is associated with a positive and a negative part due to pure Zeeman and s, p-f spin exchange interaction contributions, respectively. According to the microscopic model [9], the Verdet constant can be expressed as…”

“…(1) significantly increases as the temperature is decreased. At present, fitting the obtained experimental data to the theory of Faraday rotation in SMSs [9] in detail involves difficulties because of a lack of many parameters for materials containing rare earths. Based on the performed exciton reflection measurements, a shift of the band-gap E g towards high photon energies with increase of N Dy has been found.…”