Faraday rotation studies of InSb and Cd{sub 1{minus}x}Mn{sub x}Te
Faraday rotation has been studied in two material systems: narrow-gap InSb and wide-gap Cd{sub 1{minus}x}Mn{sub x}Te. The measurements were done in the infrared region using high magnetic fields up to 150 kG. The Faraday rotation of n-type InSb has been measured for wave-lengths between 8.0 and 13.0 {mu} m at 9 K, using magnetic fields up to 150 kG. Measurements were made on samples with nominal carrier concentrations of 1 x 10{sup 14}, 6 x 10{sup 14}, 1 x 10{sup 15}, and 5 x 10{sup 15} cm{sup {minus}3}. The experimental results have been successfully analyzed in terms of interband and interband transitions at the {Gamma} point in the Brillouin zone, using a quantum-mechanical treatment. In this approach, there are three contributions to the Faraday rotation: (a) interband, (b) plasma, and (c) spin contributions. The interband contribution is dominant in the low concentration samples where the plasma and spin contributions, which are due to the free carriers, are small. At high carrier concentrations the spin and plasma contributions are dominant. In the low-magnetic-field regime the interband and plasma contributions are linearly proportional to the magnetic field and become small. This rotation at low magnetic fields. The 4-band k {center_dot} p Pidgeon and Brown model was used to calculate the energy levels and the matrix elements for these transitions. Quantum oscillatory effects were observed at low magnetic field. The Faraday rotation of Cd{sub 1{minus}x}Mn{sub x}Te has been measured for x = 0 to 0.27 at 300 and 77 K for photon energies between 0.1 and 1.5 eV, corresponding to wavelengths of 12.0 and 0.8 {mu}m, respectively. We have developed a multioscillator model for the Faraday rotation using an analytical expression for the refractive index that includes contributions from interband transitions at the {Gamma}, L, and X points of the Brillouin zone as well as the lattice contribution from optical phonons.
- Research Organization:
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- OSTI ID:
- 114794
- Resource Relation:
- Other Information: DN: MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307; TH: Thesis (Ph.D.); PBD: 1992
- Country of Publication:
- United States
- Language:
- English
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