Optical Spectra of Spin-1/2 Fermi-Degenerate Systems with a Bound State: Crossover between Excitonic Peaks and the Power-Law Singularities
Optical Spectra of Spin-1/2 Fermi-Degenerate Systems with a Bound State: Crossover between Excitonic Peaks and the Power-Law Singularities
复制标题
具有束缚态的自旋 1/2 费米简并系统的光谱：激子峰与幂律奇点之间的交叉
DOI：
10.1080/1058726021000044956
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
M. Takagiwa
中科院分区：
文献类型：
--
作者：
T. Ogawa;M. Takagiwa
从理论上研究了束缚态自旋1/2费米简并系统的带间光吸收光谱。我们研究了光谱如何依赖于载流子密度，以理解从低密度(绝缘体)极限下的正常激子峰结构到高密度情况下的幂函数奇异性的交叉。双简并束缚态和电子自旋自由度之间的相互作用对于确定光谱的阈值行为至关重要。用含时耦合团簇展开方法计算了整个谱形，并解析地得到了这四个阈值下的临界指数的精确表达式。
Interband optical absorption spectra of a two-dimensional spin-1/2 Fermi-degenerate system with a bound state are investigated theoretically. We examine how the optical spectra depend on the carrier density to understand the crossover from a normal exciton-peak structure in the low-density (insulator) limit to the power-law singularity in the high-density case. An interplay between the doubly-degenerate bound state and the electronic spin degrees of freedom is of essential importance in determining the threshold behavior of the spectra. Whole spectral shape is calculated with the time-dependent coupled-cluster expansion method, and an exact expression of the critical exponents at these four thresholds is analytically obtained.