外加磁场下方形量子阱线中激子的束缚能

【作者】 张迎涛；

【导师】 李有成；

【作者基本信息】 河北师范大学 ， 凝聚态物理， 2002， 硕士

【摘要】 由于半导体量子阱线中激子的特性在光学器件中有着重要的应用，所以这一方面的研究一直方兴未艾。无论从实验上还是理论上，人们对于外加磁场的量子阱中激子的能级行为进行了广泛的研究。 九十年代中期，人们就开始了关于在外加磁场时量子线中激子特性的研究，Gang Li,Spiros V.Branis和K.K.Bajaj利用变分法，对于圆柱形的量子线中激子的基态束缚能进行了计算，发现对于一个给定的磁场值，激子的基态束缚能比不加磁场时变大。A.Balandin和S.Bandyopadhyay也是利用变分法，采用二能带模型计算了在外加磁场时的量子线中激子的基态束缚能。 本文采用变分法，在外加磁场条件下分别计算了激子在无限深和有限深方形量子线中的基态束缚能。在计算的过程中进一步考虑了阱，垒中粒子有效质量不匹配的影响，最后我们计算并讨论了外加磁场情况下的维里定理。通过计算得出在加磁场的情况下激子的束缚能随线宽的变化坝律，同时我们发现在考虑了粒子的有效质量不匹配时激子的束缚能相对不考虑质量不匹配的情况增大。此外我们证明在加磁场后维里定理值变小。更多还原

【Abstract】 There is significant current interest in the exitonic properties of semiconductor quantum wires because of their role in optoelectronic applications. Extensive experimental and theoretical investigations of the behavior of energy levels of excitons in quantum wells in the presence of a magnetic field have been carried out during the past 20 years.In 1990s, a calculation of the ground-state energy of an exciton confined in a cylindrical quantum wire in the presence of a uniform magnetic field is reported as a function of wire radius , using a variational approach by Gang Li,Spiros V.Branis and K.K.Bajaj. A.Balandin and S.Bandyopadhya present variational calculations of the ground-state exciton binding energy and exciton radius in a quantum wire subjected to an external magnetic field.These studies have been primarily responsible for our current understanding of the nature of excitonic states in aquantum wire subjected to an external magnetic field. For a better understanding of excitonic states in a quantum wire subjected to an external magnetic field. We process calculations as the following:We calculate the binding energies of excitons in a square quantum-well wire in presence of a magnetic field for finite and infinite potential barrier case respectively. The binding energies of excitons are calculated with the use of variational approach, we consider the mismatch of effective masses between the well and the barrier in the process of calculation, calculate and talk about the virial theorem values in square quantum-well wires in presence of a magnetic field. We find out the rule that the binding energies of excitons vary with the size of wires in the presence a magnetic field through the calculation. We compare the difference between our considering the mismatch of the effective masses of the wrell and barrier and our not considering the mismatch of the effective masses of the well and barrier. We find that virial theorem values decrease quickly as magnetic value is increased.更多还原