Bleyan Yuri Y, Mantashyan Paytsar A, Kazaryan Eduard M, Sarkisyan Hayk A, Accorsi Gianluca, Baskoutas Sotirios, Hayrapetyan David B
Department of General Physics and Quantum Nanostructures, Russian-Armenian University, Yerevan 0051, Armenia.
Photonics Laboratory, Institute for Physical Research of NAS RA, Ashtarak 0203, Armenia.
Nanomaterials (Basel). 2022 Apr 20;12(9):1412. doi: 10.3390/nano12091412.
We have presented a theoretical investigation of exciton and biexciton states for the ground and excited levels in a strongly oblate ellipsoidal quantum dot made from GaAs. The variational trial wave functions for the ground and excited states of the exciton and biexciton are constructed on the base of one-particle wave functions. The energies for the ground and excited levels, depending on the ellipsoidal quantum dot's geometrical parameters, are depicted in the framework of the variational method. The oscillator strength of the transition from exciton to biexciton states for ground and excited levels is investigated as a function of the ellipsoidal quantum dot's small and large semiaxes. The third-order optical susceptibilities of ground and excited biexcitons around one-photon and two-photon resonances are calculated as a function of the photon energy. The dependences of third-order optical susceptibilities for the ground and excited levels on the photon energy for different values of the ellipsoidal quantum dot's semiaxis are revealed. The absorption coefficients in the ellipsoidal quantum dot, both for ground and excited states of exciton and biexciton, are calculated. The absorption coefficients for the ground level of exciton and biexciton for the fixed value of the large semiaxis and for the different values of the small semiaxis are determined. Finally, the two-photon absorption coefficient of the biexciton in the GaAs ellipsoidal quantum dot is computed.
我们对由砷化镓制成的强扁椭球形量子点基态和激发态中的激子与双激子态进行了理论研究。激子和双激子基态与激发态的变分试探波函数是基于单粒子波函数构建的。在变分法框架内描绘了取决于椭球形量子点几何参数的基态和激发态能量。研究了基态和激发态从激子到双激子态跃迁的振子强度随椭球形量子点小半轴和大半轴的变化。计算了基态和激发态双激子在单光子和双光子共振附近的三阶光学极化率随光子能量的变化。揭示了不同椭球形量子点半轴值下基态和激发态三阶光学极化率随光子能量的依赖关系。计算了椭球形量子点中激子和双激子基态与激发态的吸收系数。确定了大半轴固定值和小半轴不同值下激子和双激子基态的吸收系数。最后，计算了砷化镓椭球形量子点中双激子的双光子吸收系数。
