X.L. Lei and S.Y. Liu: Balance-equation approach to terahertz-field-driven magnetotransport
277
configuration in nonpolar and polar semiconductors sub-
jected to a dc bias.
1.8
1.6
1.4
1.2
1.0
0.8
0.6
T=0.4 ΩLO
v0=0.03 vLO
ω=0.1 ΩLO
Eω=0
Eω=5x10-3 E*LO
Eω=7.5x10-3 E*LO
Eω=1.25x10-2 E*LO
We find that the previous magneto-phonon resonance
peaks in the absence of the high-frequency field are sup-
pressed by the irradiation of the terahertz field, while
many new peaks, which correspond to multiple photon
emission and absorption processes, emerge and may be-
come quite distinct, at moderately strong radiation field.
Although these multiphoton-magnetophonon resonance
peaks may be somewhat smeared by further broadening
of the Landau levels due to other mechanisms, it should
be observable in a magnetically quantized semiconductor
when it is exposed to an intense terahertz radiation.
(1,1)
(1,-1)
(2,-1)
(2,-2)
(1,2)
(2,1)
(1,-2)
(1,-3)
This work was supported by the National Natural Science
Foundation of China, the National and Shanghai Municipal
Commissions of Science and Technology of China, and the
Shanghai Foundation for Research and Development of Ap-
plied Materials.
0.4
0.6
0.8
1.0
1.2
1.4
ωc/ΩLO
Fig. 3. The multiphoton-magnetophonon resonance in the
longitudinal resistivity ρxx of a polar semiconductor driven
by a dc bias velocity v0 = 0.03vLO and by a radiation field
of frequency ω = 0.1ΩLO having three different amplitudes
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Eω = 0.005, 0.0075, and 0.0125EL∗O in the T configura-
⊥
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=
0.03vLO and ac-frequency ω = 0.1ΩLO, is plotted in
ˇ
Figure 3, for∗3 different ∗values of the ac∗ field strengths
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≡
(ΩLO/m)1/2 and EL∗O = (mΩL3O
)
1/2/|e|. All the features
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6 Conclusion
We have developed a balance-equation approach to
terahertz-driven magnetotransport in semiconductors
with a dc or slowly-varying electric field, an intense po-
larized radiation field of THz frequency and a uniform
magnetic field, being in arbitrary directions and having
arbitrary strengths, applied simultaneously in the system.
These equations, which include all orders of multipho-
ton processes, have been applied to the examination of
the effect of a terahertz radiation on the magnetophonon
resonance of the longitudinal resistivity in the transverse