论文标题
中性电子孔系统中的费米边缘奇异性
Fermi edge singularity in neutral electron-hole system
论文作者
论文摘要
在低温下的中性致密电子孔（E-H）系统中，理论预测了费米能量的库珀对激子和BCS样激子冷凝。光激发允许使用由激发能力控制的密度创建E-H系统。但是，实现高密度所需的强烈光激发会导致E-H系统的大量加热，从而阻止了传统半导体中的密集和冷E-H系统的实现。在这项工作中，我们研究了通过分离的电子和孔层中光激发产生的E-H系统。该层的分离增加了E-H重组时间，进而增加了通过数量级给定光学激发的密度，因此，可以实现致密和冷的E-H系统。我们发现在中性致密的超低E-H系统的费米能量上，光致发光强度的强烈增强，这证明了由于费米能在费米能量上类似库珀对的激子引起的激子费米边缘奇异性的出现。
In neutral dense electron-hole (e-h) systems at low temperatures, theory predicts Cooper-pair-like excitons at the Fermi energy and a BCS-like exciton condensation. Optical excitation allows creating e-h systems with the densities controlled by the excitation power. However, the intense optical excitations required to achieve high densities cause substantial heating of the e-h system that prevents the realization of dense and cold e-h systems in conventional semiconductors. In this work, we study e-h systems created by optical excitation in separated electron and hole layers. The layer separation increases the e-h recombination time and, in turn, the density for a given optical excitation by orders of magnitude and, as a result, enables the realization of the dense and cold e-h system. We found a strong enhancement of photoluminescence intensity at the Fermi energy of the neutral dense ultracold e-h system that evidences the emergence of excitonic Fermi edge singularity due to the Cooper-pair-like excitons at the Fermi energy.
