Space- and time-dependent quantum dynamics of spatially indirect excitons in semiconductor heterostructures.
Space- and time-dependent quantum dynamics of spatially indirect excitons in semiconductor heterostructures.
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半导体异质结构中空间间接激子的空间和时间相关量子动力学。
DOI：
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发表时间：
2015
影响因子：
4.4
通讯作者：
G. Goldoni
中科院分区：
文献类型：
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作者：
F. Grasselli;A. Bertoni;G. Goldoni
利用分步傅立叶方法研究了两粒子一维薛定谔方程的么正传输，研究了空间间接激子(IX)在半导体异质结中的相干演化。在两粒子动力学中，精确地考虑了电子-空穴对的相互库仑相互作用和外门产生的分别作用于两个粒子的静电势。作为相关的例子，考虑了台阶/下坡和障碍/井势剖面。分析了散射过程中随时间和空间的演化，以及渐近的时间行为。对于GaAs基器件的典型参数，由于可比较和竞争的库仑、静电和动能标度，该对的传输或反射被证明是一个复杂的两粒子过程。根据散射势的强度和各向异性，量子演化可能导致IX个内部自由度的激发、对的解离或由于一个粒子驻留在势垒区域而在小的周期IX波包中传输。我们讨论了每个过程在散射势的全参数空间中的发生，以及我们的结果与当前激子技术的相关性。
We study the unitary propagation of a two-particle one-dimensional Schrödinger equation by means of the Split-Step Fourier method, to study the coherent evolution of a spatially indirect exciton (IX) in semiconductor heterostructures. The mutual Coulomb interaction of the electron-hole pair and the electrostatic potentials generated by external gates and acting on the two particles separately are taken into account exactly in the two-particle dynamics. As relevant examples, step/downhill and barrier/well potential profiles are considered. The space- and time-dependent evolutions during the scattering event as well as the asymptotic time behavior are analyzed. For typical parameters of GaAs-based devices, the transmission or reflection of the pair turns out to be a complex two-particle process, due to comparable and competing Coulomb, electrostatic, and kinetic energy scales. Depending on the intensity and anisotropy of the scattering potentials, the quantum evolution may result in excitation of the IX internal degrees of freedom, dissociation of the pair, or transmission in small periodic IX wavepackets due to dwelling of one particle in the barrier region. We discuss the occurrence of each process in the full parameter space of the scattering potentials and the relevance of our results for current excitronic technologies.