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Electron and hole spins in quantum dots.

机译：电子和空穴在量子点中自旋。

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摘要

As the technology underlying modern electronics advances, it is unlikely that previous rates of power use and computational speed improvement can be maintained. Devices using the spin of an electron or hole, "spintronic" systems, can begin to address these problems, creating new devices which can be used as a continuation and augmentation of existing electronic systems. In addition, spintronic devices could make special use of coherent quantum states, making it feasible to address certain problems which are computationally intractable using classical electronic components. Unlike higher-dimensional nanostructures such as quantum wires and wells, quantum dots allow a single electron or hole to be confined to the dot. Through the spin-orbit effect, the electron and hole g-tensor can be influenced by quantum dot shape and applied electric fields, leading to the possibility of gating a single quantum dot and using a single electron or hole spin for quantum information storage or manipulation.;In this thesis, the spin of electrons and holes in isolated semiconductor quantum dots are investigated in the presence of electric and magnetic fields using realspace numerical 8-band strain-dependent k · p theory. The calculations of electron and hole g-tensors are then used to predict excitonic g-tensors as a function of electric field. These excitonic g-factors are then compared against existing experimental work, and show that in-plane excitonic g-factor dependence on electric field is dominated by the hole g-factor. The dependence of the electron and hole g-tensors on the applied electric field are then used to propose a class of novel quantum dot devices which manipulate the electron or hole spins in either a resonant or a non-resonant mode. Because of the highly parabolic dependence of some components of the hole g-tensor on the applied electric field, a shift in the Larmor frequency and an additional resonance are predicted, with additional shifts and resonances occurring for higher-order dependencies. Spin manipulation times down to 3.9ns for electrons and 180ps for holes are reported using these methods.
机译：随着现代电子技术的发展，不可能保持以前的用电速度和计算速度的提高。使用电子或空穴的自旋的“自旋电子”系统的设备可以开始解决这些问题，从而产生可以用作现有电子系统的延续和扩充的新设备。另外，自旋电子器件可以特别利用相干量子态，从而使解决某些问题变得可行，而这些问题是使用经典电子元件在计算上难以解决的。与诸如量子线和阱之类的高维纳米结构不同，量子点允许将单个电子或空穴限制在该点上。通过自旋轨道效应，电子和空穴的g张量会受到量子点形状和施加电场的影响，从而有可能对单个量子点进行门控，并使用单个电子或空穴自旋来存储或操纵量子信息。 。;本文采用实空间数值型8波段应变相关k·p理论研究了在电场和磁场存在下隔离的半导体量子点中电子和空穴的自旋。然后，使用电子和空穴g张量的计算来预测作为电场函数的激子g张量。然后将这些激子g因子与现有的实验工作进行比较，表明面内激子g因子对电场的依赖性由空穴g因子决定。然后，使用电子和空穴g张量对所施加电场的依赖性来提出一类新颖的量子点器件，该器件以共振或非共振模式操纵电子或空穴自旋。由于空穴g张量的某些分量对所施加电场的高度抛物线依赖性，因此可以预测拉莫尔频率的偏移和其​​他共振，对于更高阶的依赖性，还会发生其他偏移和共振。据报道，使用这些方法，电子的自旋操纵时间低至3.9ns，空穴的自旋操纵时间低至180ps。

著录项

  • 作者

    Pingenot, Joseph Albert Ferguson.;

  • 作者单位

    The University of Iowa.;

  • 授予单位 The University of Iowa.;
  • 学科 Physics Electricity and Magnetism.;Physics Theory.;Physics Condensed Matter.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 263 p.
  • 总页数 263
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 电磁学、电动力学;
  • 关键词

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