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Journal of Physical Studies 19(3), Article 3702 [9 pages] (2015)
DOI: https://doi.org/10.30970/jps.19.3702 THE ELECTRON SPECTRUM RENORMALIZED DUE TO CONFINED PHONONS IN A TWO-WELL PLANE NANOSTRUCTURE DRIVEN BY THE CONSTANT ELECTRIC FIELD AT AN ARBITRARY TEMPERATUREJu. O. Seti, M. V. Tkach, M. V. Pan'kiv
Fedkovych Chernivtsi National University, |
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The Hamiltonian of electron-phonon interaction is obtained in the representation of the second quantization over all variables using an approximation of the effective mass for the electron taking into account the nonparabolicity of the conductive band and the model of polarizational continuum for the confined optical phonons in a double-well plane resonant tunneling nanostructure placed into the constant electric field. The renormalized magnitudes of spectral parameters (shifts and decays) of the electron states in a double-well cascade of the injectorless quantum cascade laser are calculated in the terahertz range of frequencies within the method of temperature Green's functions taking into account the weak electron-phonon binding in a one-phonon approximation. The diverse mechanisms of the electron-phonon interaction are studied in the formation of shifts and decays of electron states and the radiation band of a cascade of the quantum cascade laser depending on the geometrical configuration of the resonant tunneling nanostructure, the magnitude of a constant homogeneous electric field and temperature. The shifts and decays of electron states are very nonlinear functions of the position of the inner potential barrier in the common potential well of a double-well cascade of the quantum cascade laser and are mainly formed by the intraband interaction, except for those configurations where the anticrossings of electron energies happen. It is established that irrespective of the geometrical design of a cascade of the quantum cascade laser the variance from cryogenic to room temperature brings about an increasing low-energy shift of electron energy states as well as their broadening. It is shown that the frequency of laser generation of a double-well resonant tunneling nanostructure being a separate cascade of the quantum cascade laser basically does not depend on the temperature and width of the radiation band weakly increasing (till 1 meV) when the temperature varies from the cryogenic to room values.
PACS number(s): 78.67.De, 63.20.Kr, 72.10.Di