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In this work, we study the optical properties of spherical quantum dots by using Tietz potential. In this regard, we have applied Nikiforov-Uvarov (NU) technique and numerically solved the Schrödinger equation to obtain energy levels and wave functions. Then, by using the density matrix method, we have derived expressions for the changes in linear and third-order nonlinear absorption coefficients and refractive index. According to the results obtained from this work, it is deduced that: (i) the total refractive index and the absorption coefficients increase and shift towards higher energies as v 0 increases; (ii) the total absorption coefficient and refractive index decrease and also shift towards lower energies as r 0 increases.

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In this paper, we have studied electronic properties of a two-electron quantum dot using Tietz confining potential in the presence of an external magnetic field. In this regard, we have applied diagonalization procedure of Hamilonian matrix. We have calculated singlet-triplet ground state transitions as a function of the magnetic field. The obtained results show that the dot size of the Tietz potential has an important role in the ground state transition. The singlet-triplet transition of the ground state shifts towards lower magnetic field when the quantum size increases. Our results yield much less transitions than that of previous results [R.G. Nazmitdinov, N.S. Simonovic, and M.J. Rost, Phys. Rev. B 65 (2002) 155307].

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