THERMOELECTRIC-POWER OF SEMICONDUCTORS IN EXTREME QUANTUM LIMIT .2. PHONON-DRAG CONTRIBUTION
THERMOELECTRIC-POWER OF SEMICONDUCTORS IN EXTREME QUANTUM LIMIT .2. PHONON-DRAG CONTRIBUTION
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DOI：
10.1103/physrevb.12.1418
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发表时间：
1975-01-01
影响因子：
3.7
通讯作者：
JAYGERIN, JP
中科院分区：
文献类型：
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作者：
JAYGERIN, JP
研究了在强磁场H中电子能级的量子化对高纯各向同性半导体（n型砷化镓，GaAs）横向热电势的”声子拖曳”贡献Sp的影响.导出了Sp的理论表达式，假定（i）导带中的所有电子都容纳在n= 0的朗道能级中（极端量子极限），（ii）量子数n= 0在散射期间不改变（由于电子和声子系统之间的能量交换不足），（iii）电子-声子相互作用通过形变势散射发生（在强场区，通过压电耦合机制的散射可以忽略），以及（iv）自旋分裂的影响可以忽略。结果对电场中的一阶和电子-声子相互作用（第一玻恩近似）中的二阶都有效，表明当最低朗道能级的底部接近费米能级几k B T时，电子分布向非简并态的转变在很低的温度下对Sp随磁场的变化有很大的影响。的曲线|S p|随着H的增加，对H的第一个上升非常迅速，然后趋于饱和的电子分布变得非简并。随着温度的降低，这种饱和趋势越来越明显。对电子浓度为1.2× 10 16 cm− 3的n型GaAs进行了数值计算。
We develop a study of the effect of the quantization of the electron energy levels in a strong magnetic field H on the" phonon-drag" contribution S p of the transverse thermoelectric power of a high-purity isotropic semiconductor (n-type gallium arsenide, GaAs) in the extreme quantum limit. A theoretical expression for S p is derived, assuming that (i) all the electrons in the conduction band are accommodated in the n= 0 Landau level (extreme quantum limit),(ii) the quantum number n= 0 does not change during scattering (because of insufficient energy exchange between the electrons and the phonon system),(iii) the electron-phonon interaction occurs through the deformation-potential scattering (in the strong-field region, the scattering via the piezoelectric-coupling mechanism can be ignored), and (iv) the effect of spin splitting is neglected. The results, which are valid to the first order in the electric field and to the second order in the electron-phonon interaction (first Born approximation), show that the transition to nondegeneracy in the electron distribution, which takes place when the bottom of the lowest Landau level approaches within a few k B T the Fermi level at very low temperatures, has a large effect on the variation of S p with magnetic field. The curves of| S p| vs H at first rise very rapidly with increasing H, and then tend to saturate as the electron distribution becomes nondegenerate. This tendency to saturate is more and more pronounced as the temperature is decreased. Numerical calculations are carried out for n-type GaAs with an electron concentration of 1.2× 10 16 cm− 3.