Device Physics of Narrow Gap Semiconductors by Junhao Chu & Arden Sher

Author:Junhao Chu & Arden Sher
Language: eng
Format: epub
Publisher: Springer New York, New York, NY

Fig. 4.45The mixing of wave functions enables different transitions among spin-split Landau levels. Some permitted transitions are indicated by dotted lines

Fig. 4.46Cyclotron- resonance and spin-resonance spectroscopy on the inversion layer of p-type Hg1 − x Cd x Te (x = 0. 234, N A = 4 ×1017 cm − 3)

Sizmann et al. (1988) were the first to report the spectra of electron-cyclotron resonance in the narrow-gap semiconductors. Since the signal of the spin resonance is 20 times weaker than that compared with cyclotron resonance, it is difficult to detect. But the spin resonance signal can be observed in the cyclotron-resonance-inactive mode if we change the direction of the magnetic field in a cyclotron resonance measurement. Figure 4.46 shows the cyclotron-resonance and spin-resonance spectra in the inversion layer p-type Hg1 − x Cd x Te with a photon energy of 17.6 meV. The resonance peak results from the electronic transition from state 2 +  → 3 + . With an electron concentration increase, the Fermi level moves to a higher energy and the peak moves to the high-magnetic-field side of the spectrum. As the electron concentration changes from 3 ×1011 to 4. 6 ×1011 cm − 2, the spin-resonance peak approaches the cyclotron-resonance peak from the high-magnetic-field side, which results from the intersection of the Landau levels. Figure 4.47 shows the energies of the Landau levels as a function of the magnetic field. The levels 2 −  and 3 +  intersect at 4 T. The spin-resonance peak of 2 +  → 2 −  and the cyclotron-resonance peak of 2 +  → 2 +  approach one another as the Fermi level moves to higher energy. The observed spin resonance confirms the wave function mixing and the intersection of the Landau levels.

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