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WOS: 000271864200007, Valence band structure with spin-orbit (SO) coupling of GaAs/Ga1-xAlxAs square quantum well (SQW) under the electric field by a calculation procedure based on a finite element method (FEM) is investigated using the multiband effective mass theory ((k) over right arrow . (p) over right arrow method). The validity of the method is confirmed with the results of D. Ahn, S. L. Chuang and Y. C. Chang (J. Appl. Phys. 64 (1998) 4056), who calculated valence band structure, using axial approximation for Luttinger-Kohn Hamiltonian and finite difference method. Our results demonstrated that SO coupling and electric field have significant effects on the valence band structure., T. R. Prime Ministry State Planning Organization [DPT-120220], The authors would like to thank the T. R. Prime Ministry State Planning Organization for financial support (project No. DPT-120220).

WOS: 000289155800009, A study of variational wave functions for calculation of the ground-state energies of excitons confined in a two-dimensional (2D) disc-like and three-dimensional (3D) spherical parabolic GaAs quantum dots (QDs) is presented. We have used four variational trial wave functions constructed as the harmonic-oscillator basis multiplied by different correlation functions. The proposed correlation function formed by including linear expansion in terms of Hylleraas-like coordinates to the Jastrow factor is able to capture nearly exactly the ground-state energies of 31) excitons, and it properly account for the results of 2D excitons. Quantum Monte Carlo techniques combined with the proposed wave function are a powerful tool for studying excitons in parabolic QDs., Cumhuriyet University; National MOVPE Crystal Growth and Characterization Laboratory, Turkey [DPT-K 120]; TUBITAK [TBAG 105T492, TBAG 107T012, TBAG-10ST015], The authors acknowledge the support of the Cumhuriyet University, National MOVPE Crystal Growth and Characterization Laboratory, Turkey, DPT-K 120, TUBITAK Grants TBAG 105T492, TBAG 107T012, and TBAG-10ST015.

WOS: 000264290900048, In this work, the effects of quantum confinement on the ground state energy of a correlated electron-hole pair in a spherical and in a disc-like quantum dot have been investigated as a function of quantum dot size. Under parabolic confinement potential and within effective mass approximation Ritz's variational method is applied to Hylleraas-like trial wavefunction. An efficient method for reducing the main effort of the calculation of terms like r(ch)(k) exp (-lambda r(eh)) is introduced. The main contribution of the present work is the introduction of integral transforms which provide the calculation of expectation value of energy and the related matrix elements to be done analytically over single-particle coordinates instead of Hylleraas coordinates.

WOS: 000268802300062, In this work, we propose an efficient method of reducing the computational effort of variational calculation with a Hylleraas-like trial wavefunction. The method consists of introducing integra transforms for the terms as r(12)(k) exp (-lambda r(12)) which provide the calculation of the expectation value of energy and the relevant matrix elements to be done analytically over single-electron coordinates instead of Hylleraas coordinates. we have used this method to calculate the ground state energy of a two-electron system in a spherical dot and a disk-like quantum dot separately. Under parabolic confinement potential and within effective mass approximation size and shape effects of quantum dots on the ground state energy of two electrons have been investigated. The calculation shows that our results even with a small number of basis states are in good agreement with previous theoretical results., Cumhuriyet University; National MOVPE Crystal Growth and Characterization Laboratory, Turkey [DPT-K 120]; TUBITAK [TBAG 105T492, TBAG 107T012, TBAG-108T015], Project supported by the Cumhuriyet University, National MOVPE Crystal Growth and Characterization Laboratory, Turkey, DPT-K 120, TUBITAK (Grant Nos TBAG 105T492, TBAG 107T012, and TBAG-108T015).