Electron-Phonon Interaction and Magnetophonon Resonance in Quantum Wires

量子线中的准一维电子在输运和光学性质方面具有各种有趣的特性。这种电子气可以通过使用栅电极或通过蚀刻侧壁在异质界面中压缩二维电子气来形成。这种准一维电子气由于态密度的奇异性而表现出不同的电子-声子相互作用，因此我们可以预期电子输运的一个非常有趣的特征。在低温下，电子表现出弹道输运、干涉效应、电导量子化、量子涨落等特性，本研究计划主要研究高温下量子线中的电子-声子相互作用，以及磁声子共振的理论表述和实验观察。所得结果总结如下.我们利用u ...更多信息 唱久保公式。在具有抛物约束势、能量间距为hOMEGA的窄量子线中，磁导率在共振态NhROO&lt;W^2_+ OMEGA ^2&gt;=hw_0处表现出极大值，其中w_c=eB/m^*，N= 1，2，3.<ep>在谐振处的磁导率，以及另一个，<po>由于在量子线的边缘附近的电子的跳跃运动的扰动而引起的σ_，引起磁导率的最小值。在不同结构的量子线中进行了实验，发现在100- 200 K温度范围内，磁电阻（p_<xx>=1/σ_<xx>）有极大值，表明σ_<po>起主导作用。2.我们用电子束光刻和激光束全息术制作了量子线。我们还制备了用于加工量子线的光学掩模。3.实验观察到了4.2 K时清晰的Shubnikov-de哈斯振荡和更高温度时清晰的振荡结构，与理论预测吻合较好。分析给出了有效质量和约束势。4.我们准备了量子线与肖特基栅极和低温测量给出了准一维性质的电子与限制电位为05毫电子伏。5。我们在强磁场下对GaAs/AlAs短周期超晶格进行了回旋共振测量，观察到了电子在带折叠X_z导带中的共振现象。我们发现G和X_z导带的交叉发生在单层数n=12.6处。我们制作了GaAs/AlAs超晶格p-i-n二极管，并首次成功地观察到了与Wannier-Stark态相关的齐纳隧穿。少

Quasi-one-dimensional electrons in quantum wires give various interesting features in transport and optical properties. Such electron gas may be formed by constricting two-dimensional electron gas in heterointerfaces by using gate electrodes or by etching the side walls. Such Quasi-one-dimensional electron gas exhibit different electron-phonon interactions due to the singularity of the density of states, and thus we can expect a very interesting feature of electron transport. At low temperatures, it is well known that such electrons show ballistic transport, interference effects, quantization of conductivity, quantum fluctuation and so on. In this research project we will concern with investigation of electronphonon interaction in quantum wires at high temperatures and also with theoretical formulation and experimental observation of magnetophonon resonance. The obtained results are summarized in the following.1. We derived magnetoconductivity of quasi-one-dimensional electron gas by u … More sing Kubo formula. In a narrow quantum wire with parabolic confinement potential, energy spacing hOMEGA, the magnetoconductivity exhibits extrema at resonance NhROO<W^2_+OMEGA^2>=hw_o, where w_c=eB/m^* and N=1,2,3, -The magnetoconductivity is found to consist of two dominant terms, the one, sigma_<ep>, due to the scattering of electrons located near the center of the quantum wire by LO phonons resulting in maxima of the magnetoconductivity at the resonance, and the other, sigma_<po> due to the disturbance of the skipping motion of electrons near the edge of the quantum wire giving rise to minima in the magnetoconductivity. Experiments have been carried out in quantum wires with different structures, and revealed maxima in the magnetorisistance(p_<xx>=1/sigma_<xx>)in the temperature range 100-200K,which indicates the term sigma_<po> dominates. 2. We fabricated quantum wires by using electron beam lithography and by laser beam holography. Also we prepared optical masks for processing quantum wires. 3. Experimental observation revealed clear Shubnikov-de Haas oscillations at 4.2 K and clear oscillatory structures at higher temperatures, which show a good agreement with the theoretical prediction. The analysis gives the effective mass and confinement potential. 4. We prepared quantum wires with Schottky gates and low temperature measurements gives quasi-one-dimensional nature of electrons with confinement potential of 05 meV.5. We carried out cyclotron resonance measurements of GaAs/AlAs short period superlattices at high magnetic fields and observed the resonance of electrons in the zone-folded X_z conduction band. We found that the cross-over of the G and X_z conduction bands occur at the monolayr number n=12.6. We fabricated p-i-n diodes of GaAs/AlAs superlattices and succeeded in the first observation of Zener tunneling associated with Wannier-Stark states. Less