Electron-Phonon Interaction and Magnetophonon Resonance in Quantum Wires

量子线中的电子声子相互作用和磁声子共振

• 批准号: 04402031
• 负责人: HAMAGUCHI Chihiro
• 金额: $ 22.66万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (A)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-04402031/
• 关键词: quantum wires; magnetophonon resonance; quasi-one-dimensional electron gas; magnetoconductivity; electron-phonon interaction; electron mobility; mesoscopic structure; intersubband scattering

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

量子线中的准一维电子给出了各种有趣的输运和光学特性。这种电子气可以通过使用栅电极在异质界面上压缩二维电子气或通过蚀刻侧壁来形成。由于态密度的奇异性，这种准一维电子气表现出不同的电子-声子相互作用，因此我们可以预料到电子输运的一个非常有趣的特征。在低温下，这种电子表现为弹道输运、干涉效应、电导率量子化、量子涨落等。在这个研究项目中，我们将研究高温下量子线中的电声子相互作用，以及磁声子共振的理论公式和实验观察。所获得的结果总结如下：1.我们用u-…方法推导了准一维电子气的磁电导。更多的是唱久保配方。在具有抛物线限制势、能距Homega的窄量子线中，磁导率在共振NhROO&lt；W^2+omega^2&gt；=Hw_o处呈现极值，其中w_c=Eb/m^*，N=1，2，3-磁电导由两个主要项组成，一个是由于位于量子线中心附近的电子被Lo声子散射，导致共振时的磁电导达到极大值，另一个是sigma&lt；po&gt；由于量子线边缘附近电子的跳跃运动的扰动，导致了磁电导的最小值。在不同结构的量子线中进行了实验，发现magnetorisistance(p_&lt；xx&gt；=1/sigma_&lt；xx&gt；)in在100K-200K温度范围内有极大值，这表明sigma_&lt；po&gt；项占主导地位。2.利用电子束光刻和激光全息技术制备了量子线。我们还制备了用于处理量子线的光学掩模。3.实验观测表明，在4.2K下有明显的Shubnikov-de Haas振荡现象，在较高温度下有明显的振荡结构，与理论预测吻合较好。分析给出了有效质量和禁闭势。4.制备了肖特基栅量子线，低温测量给出了束缚势为05 meV.5的电子的准一维性质。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，观察到了带折叠X_z导带中的电子共振现象。我们发现G和X_z导带的交叉发生在单层数n=12.6时。我们制作了GaAsAlAs超晶格的p-i-n二极管，并首次成功地观察到了与Wannier-Stark态相关的齐纳隧道效应。较少

项目成果

H.Momose,N.Mori,K.Taniguchi,C.Hamaguchi: "New Model for Monte Carlo Simulation of Hot Electrons in Quantum Wires" Semiconductor Science and Technology. 9. 958-960 (1994)

H.Momose，N.Mori，K.Taniguchi，C.Hamaguchi：“量子线中热电子的蒙特卡罗模拟新模型”半导体科学与技术。

H.Momose,N.Mori,K.Taniguchi,C.Hamaguchi: "New Model for Monte Carlo Simulation of Hot Electrons in Quantum Wires" Semiconductor Science and Technology. (発表予定).

H.Momose、N.Mori、K.Taniguchi、C.Hamaguchi：“量子线中热电子的蒙特卡罗模拟新模型”半导体科学与技术（待发表）。

T.Miyatake,S.Horihata,T.Ezaki,H.Kubo,N.Mori,K.Taniguchi,C.Hamaguchi: "GaAs/AlGaAs quantum well infrared photodetectors" Solid-State Electron.(発表予定).

T.Miyatake、S.Horihata、T.Ezaki、H.Kubo、N.Mori、K.Taniguchi、C.Hamaguchi：“GaAs/AlGaAs 量子阱红外光电探测器”固态电子（待提交）。

N.Mori,H.Momose,C.Hamaguchi: "Magnetophonon resonances in quantum wires" Physical Review B. 45. 4536-4539 (1992)

N.Mori、H.Momose、C.Hamaguchi：“量子线中的磁声子共振”物理评论 B. 45. 4536-4539 (1992)

M.Morifuji,Y.Nishikawa,C.Hamaguchi,T.Fujii: "Electronic band structures of superlattices under a uniform electric field and Wannier-Stark effect" Semiconductor Science and Technology. 7. 1047-1051 (1992)

M.Morifuji，Y.Nishikawa，C.Hamaguchi，T.Fujii：“均匀电场和万尼尔-斯塔克效应下超晶格的电子能带结构”半导体科学与技术。