Baghdasaryan Davit A, Harutyunyan Volodya A, Kazaryan Eduard M, Sarkisyan Hayk A, Petrosyan Lyudvig S, Shahbazyan Tigran V
Institute of Engineering and Physics, Russian-Armenian University, H. Emin 123, Yerevan 0051, Armenia.
Institute of Electronics and Telecommunications, Peter the Great Saint-Petersburg Polytechnical University, 195251 Saint-Petersburg, Russia.
Nanomaterials (Basel). 2023 Oct 9;13(19):2734. doi: 10.3390/nano13192734.
The quasi-two-dimensional exciton subsystem in CdSe nanoplatelets is considered. It is theoretically shown that Bose-Einstein condensation (BEC) of excitons is possible at a nonzero temperature in the approximation of an ideal Bose gas and in the presence of an "energy gap" between the ground and the first excited states of the two-dimensional exciton center of inertia of the translational motion. The condensation temperature (Tc) increases with the width of the "gap" between the ground and the first excited levels of size quantization. It is shown that when the screening effect of free electrons and holes on bound excitons is considered, the BEC temperature of the exciton subsystem increases as compared to the case where this effect is absent. The energy spectrum of the exciton condensate in a CdSe nanoplate is calculated within the framework of the weakly nonideal Bose gas approximation, considering the specifics of two-dimensional Born scattering.
研究了CdSe纳米片准二维激子子系统。理论表明，在理想玻色气体近似下，且二维激子质心平动的基态与第一激发态之间存在“能隙”时，激子在非零温度下可能发生玻色-爱因斯坦凝聚（BEC）。凝聚温度（Tc）随尺寸量子化基态与第一激发能级之间“能隙”宽度的增加而升高。结果表明，考虑自由电子和空穴对束缚激子的屏蔽效应时，与不存在该效应的情况相比，激子子系统的BEC温度会升高。在弱非理想玻色气体近似框架内，考虑二维玻恩散射的具体情况，计算了CdSe纳米片中激子凝聚体的能谱。
