抛物量子线中强耦合极化子的有效质量

Effective Mass of Strong-coupling Polaron in a Parabolic Quantum Wire

采用改进的线性组合算符法、Lagrange乘子和变分法,在考虑电子与LO声子相互作用情况下,研究了抛物量子线中强耦合极化子的有效质量和光学声子平均数。通过数值计算,讨论了约束强度ω0 和拉格朗日乘子u对极化子的有效质量m*和光学声子平均数N及极化子振动频率λ的影响。计算结果表明:有效质量m*和光学声子平均数N及极化子振动频率λ都随着约束强度ω0 和拉格朗日乘子u的增加而增大。

Recently, with the rapid development of epitaxial techniques such as molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD), more and more quasi-one-dimensional (electronic) systems have been fabricated. In such quantum well wires, the electron motion along the length of the wire is free, but it is quantized in the two dimensions perpendicular to the wire. These quantum structures present some special physical properties and have been applied to many semiconductor devices, such as high-electron-mobility transistors. In recent year, a great deal of experimental and theoretical interest has been concentrated on the study of the electronic properties of these quasi-one-dimensional semiconductor systems. With the use of variational solutions to the effective mass equations, Dagani and Hipolito have calculated the (energy) and effective mass in a rectangular quantum wires; Yeung have studied the cyclotron resonance of a magetopo-(laron) in parabolic quantum wire by using the variational-perturbation expansion method. Guo et al. discussed the binding energy of polaron in quantum wires by means of density-matrix treatment. Taking into account the interaction of the electron with optical phonon modes, Chuu et al. have studied the energies of the ground state and the excited state in cylindrical quantum wires using Pekar alternative approach and perturbation-variational method. Zhou and Gu have presented the properties of polaron and magetopolaron in cylindrical quantum wires by using variational solutions and linear combination operators methods. The properties of polaron in rectangular quantum wires and in cylindrical quantum wires have been studied by the present authors and co-workers.Considering the interaction of the electron with optical phonon modes, we investigated effective mass of strong-coupling (polaron) and the mean number of optical phonon in a parabolic quantum wire by using the Tokuda's improved linear combination operators, the Lagrange multiplier and the variational (method.) The (numerical) results showed that, with the increasing of confinement strength ω_0 of quantum wire and the (Lagrange) multiplier u, effective mass m of polaron and the mean number of optical phonon and vibration (frequency) λ of polaron will increase.