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Optical properties of a two-dimensional GaAs quantum dot under strain and magnetic field M. Servatkhah1,a

, R. Pourmand2

1 Department of Physics, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran 2 Department of Physics, Estahban Higher Education Center, 74519-44655 Estahban, Iran

Received: 4 May 2020 / Accepted: 10 September 2020 © Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract It is well known that the use of the strain plays an important role in the material properties. Strain effect is a potential tool for altering the atomic positions and defect formations. It can adjust the electronic structures and lattice vibrations. It can also affect the phase transition of the structure, the physical and chemical properties. Consequently, in this paper, we have studied the effects of strain and magnetic field on optical properties of a twodimensional quantum dot. The Hamiltonian of our system consists of the Bychkov–Rashba, Dresselhaus and strain-dependent terms. Using the diagonalization method, we have obtained the energy levels and wave functions of the system and thereby the refractive index changes and absorption coefficient in the presence of different strains. According to the results, it is found that an anti-crossing magnetic field is 7.37 T and it does not depend on the strain. Also, the energy transition increases with enhancement in the strain and decreases with increase in the magnetic field. The refractive index changes and absorption coefficient shifts toward lower (higher) energies for negative (positive) strain. The energy transition has lower values for negative strain at fixed magnetic field and confinement length.

1 Introduction It is well known that external factor plays an important role in studying the physical properties of quantum dots (QDs). Examples of external factors are electric field, impurity, spin–orbit interaction (SOI), magnetic field, temperature, pressure, electron–electron interaction, electron–phonon interaction and strain. Study of such external factors on electronic and optical properties of quantum dots has attracted a great attention in recent years [1–10]. Optical, thermodynamic and transport properties of QDs can be determined theoretically based on information about underlying electronic properties like energy levels and wave functions. In recent years, scientists worldwide have widely investigated the transport, thermodynamic and optical properties of QDs by knowledge of electronic properties [11–15]. In the last few years, there has been growing interest in the subject regarding the effects of magnetic field, SOI and strain on optical and electronic properties of quantum dots. For example, Mikhail et al. [16] have studied the SOI in a multilayered spherical quantum dot. Khordad [17] has studied the effects of magnetic field and SOI on optical and electronic properties of a double ring-shaped quantum dot. The strain effect on the absorption threshold

a e-mail: [email protected] (corresponding author)

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