Resonant electronic Raman scattering in a Van Vleck II-VI diluted magnetic semiconductor:Cd1−xFexTe

Abstract

The Van Vleck paramagnetism of Cd 1−x Fe x Te, a diluted magnetic semiconductor, is explored with electronic Raman spectroscopy of an internal transition of Fe 2+ , on the one hand, and the spin-flip Raman scattering ͑SFRS͒ from donor-bound electrons, on the other. Zeeman splitting of the Raman transition from the nonmagnetic ground state to the first excited state displays patterns consistent with energy levels responsible for the Van Vleck paramagnetism. SFRS, in turn, delineates characteristic features of the Van Vleck magnetization, as expected from s-d exchange interaction. The combination of SFRS and magnetization measurements yielded the s-d exchange constant in Cd 1−x Fe x Te, ␣N 0 = 244± 10 meV.

Raman scattering in the diluted magnetic semiconductorZn1−xFexTe: A van Vleck paramagnet

“…Lastly, spin-flip Raman scattering from donor-bound electrons in Zn 1−x Fe x Te is reported and its magnetic field dependence is interpreted in the context of the van Vleck paramagnetism of Fe 2+ in terms of magnetization measurements carried out on the same samples. These investigations complement the papers on Cd 1−x Fe x Te by Tsoi et al 18 and by Testelin et al, 20 as well as those on Cd 1−x Fe x Se by Heiman et al 21 and by Scalbert et al…”

“…͑1͒-͑3͒ of Tsoi et al 18 The selection rules based on them are presented in Table I. Backscattering and pseudo-90°-scattering configurations employed for checking the rules are schematically depicted in Fig.…”

“…Figure 10 shows the numerically calculated effective number of Bohr magnetons as a function of temperature for several magnetic fields; at low temperatures, the temperature independent characteristic of the van Vleck paramagnetism can be clearly seen. 16 Cd 1−x Fe x Te, 18 and Cd 1−x Fe x Se. 21 In addition, SFRS produces signatures narrower than those in unmodulated magnetoreflectivity, 23,[31][32][33] allowing N 0 ␣ to be determined with a higher precision in the former than in the latter.…”

“…11, the Raman spectrum of Zn 1−x Fe x Te ͑x = 0.0025͒, recorded at 2 K and 6 T and excited by the 5208 Å Kr + line, is displayed. The spin-flip Raman shift is given by 18,38 …”

“…They have been investigated theoretically [6][7][8][9] as well as experimentally, with magnetic susceptibility, 10 near and far infrared spectroscopies [11][12][13] and Raman spectroscopy. [14][15][16][17][18] In the present paper, we report the Zeeman effect of the Raman transition in Zn 1−x Fe x Te from the ⌫ 1 ground state to the ⌫ 4 , the first excited state of the internal levels of Fe 2+ , as a function of magnetic field B and crystallographic orientation. We also report and discuss the ⌫ 1 → ⌫ 4 electronic Raman line observed in combination with the zone center longitudinal optical ͑LO͒ phonon and its overtone ͑2LO͒ for small x; with large x, the Zn 1−x Fe x Te as a ternary displays an intermediate mode behavior ͑see, e.g., Ref.…”