Electron-electron Interaction and Dynamic of Electrons in a Vertically Aligned Double Dot System

垂直排列双点系统中的电子-电子相互作用和电子动力学

• 批准号: 12640311
• 负责人: FUJII Ken-ichi
• 金额: $ 2.3万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640311/
• 关键词: Vertically aligned double dot; Far-infrared magneto-optical absorption; Light induced potential modulation; Change in interdot coupling; 遠赤外磁気光吸収; 二重量子ドット; 電子相互作用

1) We fabricated vertically aligned double dot structures using GaAs/AlGaAs heterostructures and observed two resonance peaks of electrons in both two dots in a far-infrared (FIR) magneto-optical absorption measurements. Under photoexcitation with pulsed bandgap light of AlGaAs layer, the two peaks are shifted toward higher magnetic filed, depending on excitation intensity and delay time. From computer simulations, we confirmed that the peak shift includes information on an interdot coupling of the vertically aligned double dot system.2) For the quantitative investigation of the interdot coupling, we made time resolved photoluminescence (PL) measurement system and time resolved optically detected cyclotron resonance measurement system with ultrashort pulse laser. By using the measuring systems, we investigated emission peak (called as H-band emission) due to 2 dimensional electron gas (2DEG) in GaAs/AlGaAs heterostructures which is a starting material of our dot system. It is confirmed that the emission strongly depend on the wavelength of the excitation light. In this measurement, we illuminated the sample with Ar+ laser, as well as the illumination of the probing Ti:sapphire laser. The former excites electron-hole pairs in AlGaAs layer and is found to change the potential profile confining 2DEG. We have direct evidence the generated holes in AlGaAs layer flow toward GaAs layer and recombine with 2DEG in the time resolved PL measurements.3) In FIR absorption measurement, we found the zero-field spin splitting of electrons in InGaAs/InAlAs heterostructures and could estimate the value of spin-splitting energy Δ_R of a sample as 9 meV. We could show the FIR absorption measurement is quite useful technique for the estimation of Δ_R. We also show the tuning of the value of Δ_R by the bandgap light illumination which changes the confinement potential profile.

1）我们使用GaAs/AlGaAs异质结构制造了垂直排列的双点结构，并在远红外（FIR）磁光吸收测量中观察到两个点中电子的两个共振峰，在AlGaAs层的脉冲带隙光的光激发下，根据激发强度和延迟时间，两个峰值向更高的磁场移动，从计算机模拟中，我们确认峰值移动包括垂直对齐的点间耦合的信息。 2）为了研究点间耦合，我们制作了时间分辨光致发光（PL）测量定量系统和超短脉冲激光时间分辨光学检测回旋共振测量系统。由于 GaAs/AlGaAs 异质结构中的二维电子气（2DEG）（我们的点系统的起始材料）而被称为 H 带发射），已证实发射强烈依赖于激发光的波长。在这次测量中，我们用 Ar+ 激光以及探测 Ti:蓝宝石激光照射样品，前者激发了 AlGaAs 层中的电子空穴对，并发现改变了限制 2DEG 的电势分布。 AlGaAs 层中产生的空穴流向 GaAs 层，并在时间分辨 PL 测量中与 2DEG 重新结合。3）在 FIR 吸收测量中，我们发现电子的零场自旋分裂InGaAs/InAlAs 异质结构，可以估计样品的自旋分裂能 Δ_R 值为 9 meV 我们可以表明 FIR 吸收测量对于估计 Δ_R 是非常有用的技术 我们还显示了通过调整 Δ_R 值。改变限制电位分布的带隙光照明。

项目成果

H.Nakata, et al.: "Photoluminescence of two dimensional electron system excited by far-infrared cyclotron resonance in GaAs/AlGaAs double heterostructure"J. Lumi.. 87-89. 366-368 (2000)

H.Nakata, et al.: “GaAs/AlGaAs双异质结构中远红外回旋共振激发的二维电子系统的光致发光”J.

K.Fujii, et al.: "Lineshape analysis of electron cyclotron resonance in InGaAs/InAlAs heterostructures"IPAP Conf. Series 2. 230-232 (2001)

K.Fujii 等人：“InGaAs/InAlAs 异质结构中电子回旋共振的线形分析”IPAP Conf.

K.Fujii, et al.: "Far-infrared magneto-optical absorption of vertically aligned double dot array system"Jpn. J. Appl. Phys.. 40. 2087-2091 (2001)

K.Fujii等：“垂直排列双点阵列系统的远红外磁光吸收”Jpn。

K. Fujii, Y. Morikami, T. Ohyama, S. Gozu and S. Yamada: "Determination of Rashba Spin Splitting in InxGal-xAs/InyAll-yAs by means of Far-Infrared Magneto-Optical Absorption"Physica E. (To be published). (2002)

K. Fujii、Y. Morikami、T. Ohyama、S. Gozu 和 S. Yamada：“通过远红外磁光吸收测定 InxGal-xAs/InyAll-yAs 中的 Rashba 自旋分裂”Physica E.（至

K. Fujii, T. Yoshizawa, T. Ohyama, K. Oto, S. Takaoka, K. Murase and K. Gamo: "Optically controlled confined potential of a vertically aligned double-dot array system"Superlattices and Microstructures. 27. 353-357 (2000)

K. Fujii、T. Yoshizawa、T. Ohyama、K. Oto、S. Takaoka、K. Murase 和 K. Gamo：“垂直排列双点阵列系统的光学控制限制势”超晶格和微结构。