https://doi.org/10.15407/spqeo6.03.269
Semiconductor Physics, Quantum Electronics & Optoelectronics. 2003. V. 6, N 3. P. 269-273.
PACS: 71.38, 73.20.D, 74.80.D
Properties of the shallow
D-centers
in semiconductors with polar and covalent binding
N.I. Kashirina1,
V.D. Lakhno2,
V.V. Sychyov2,
M.K. Sheinkman1
1Institute of Semiconductor Physics, NAS
of Ukraine, 45 prospect Nauky, 03028 Kyiv, Ukraine
E-mail: kashirin@class.semicond.kiev.ua
2Institute of Mathematical Problems of Biology RAS, 142290 Pushchino,
RUSSIA
E-mail: lak@impb.psn.ru
Abstract. The theoretical consideration of the energy of the lowest singlet and
triplet terms of shallow D-centers
(two electrons, bound with one-charge Coulomb center) in semiconductors
with an ionic and covalent binding has been carried out. The electron-phonon
interaction is described by a Fröhlich Hamiltonian. The energy of D-center
is described with the use of a Buimistrov-Pekar method of canonical transformations
for arbitrary electron-phonon coupling. It is shown, that for all area
of electron-phonon interaction parameters the Buimistrov-Pekar method
yields the lowest values of the ground state energy of D-centers
and free bipolaron in comparison with the best, for today, numerical calculations
of the relevant values which have been carried out within the framework
of the direct variation methods. The calculations have shown the lack
of the bound metastable triplet states corresponding to the lowest triplet
energy term of D-center
and bipolaron for all the area of electron-phonon interaction parameters,
in complete analogy to the Hill theorem about the lack of the bound excited
states of H-
ion. It is shown that the account of interaction with acoustic phonons
can produce considerable lowering the ground state energy of D-center
in comparison with the magnitude 1.0555Ry
(where m
- is the effective mass of an electron, e0
- is a static permittivity of a crystal).
Keywords:
bipolaron, Frölich Hamiltonian, electron-phonon interaction.
Paper received 30.05.03; accepted for publication
17.06.03.
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