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Phonon spectra in quantum dots, quantum wires and nanosystems created of them

Mykola V. Tkach 1Volodymyr P. Zharkoy Olexander M. Makhanets Olexander D. Val` Vasyl I. Gutsul 

1. Chernivtsi National University (ChNU), 2 Kotsubinsky Str., Chernivtsi 58012, Ukraine

Abstract

Phonon spectra in single quantum dots and quantum wires have been studied for a long time in the framework of different models. Recently the theory of phonon spectra in multishell quantum dots (QD`s) and quantum wires (QW`s) have been established within the dielectric continuum (DC) model. The latter provides the ability to study the interaction between phonons and different quasiparticles (electrons, holes, excitons) not only in closed but in opened nanosystems too. The intensive experimental research in the creation of complicated nanosystems, the so called, spatial "architecture complexes" consisting of QD`s, QW`s and quantum wells stimulate the development of the theory of phonon spectra in such systems.
In the proposed paper the theory of the phonon spectrum and polarizational field is established for the complicated nanoheterosystem consisting of cylindrical QD surrounded by two cylindrical quantum antidots (QAD) located in cylindrical QW embedded into the massive media (MM). The nanosystem under study is described by the quasi 1D model.
The phonon spectra and polarization of the potential field are obtained within the DC model using the electrostatic boundary conditions. The quantization of the polarizational field is performed. It is established that the phonon spectra of the system contains two energies of confined phonons (equal to the energies of longitudinal phonons of massive crystals analogue to QD and QAD); the energy of semi-confined phonons (equal to the energy of longitudinal phonons of surrounding media) and two types of interface phonons modes arising due to the side and main interfaces between cylindrical QD and cylindrical QW.
The dispersion law of interface phonons is calculated for the particular nanosystem. It weakly depends on the radius of QD and QW and the phonon energies are located between the smallest energy of transversal and the biggest energy of longitudinal phonons of the compositions of nanosystem.

 

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Related papers

Presentation: poster at E-MRS Fall Meeting 2004, Symposium A, by Mykola V. Tkach
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-04-27 11:03
Revised:   2009-06-08 12:55