YUAN Li-hua, AN Zhang-hui, MA Jun, CHEN Yu-hong. Polaron Effects on D<sup>-</sup> Center in a Parabolic Quantum Well[J]. Chinese Journal of Luminescence, 2007,28(3): 317-320
YUAN Li-hua, AN Zhang-hui, MA Jun, CHEN Yu-hong. Polaron Effects on D<sup>-</sup> Center in a Parabolic Quantum Well[J]. Chinese Journal of Luminescence, 2007,28(3): 317-320DOI:
Polaron Effects on D- Center in a Parabolic Quantum Well
) in a semiconductor heterostructure or quantum well is formed by a neutral center (D
0
) trapping an extra electron. This system has attracted considerable attention since the early days of quantum mechanics. D
-
centers are one of the simplest many-body electronic systems which can be used as a test for theoretical descriptions of e-e correlation. In previous experimental and theoretical studies
the dependence of the binding energy of D
-
on the magnetic-field strength and on the dimension of the quantum well have been investigated. Although there have been great efforts toward understanding the behavior of the D
-
centers in Q2D systems
very little information is available concerning polaron effects on the properties of the D
-
center in a parabolic quantum well(PQW). The polarization potential and the binding energy of the D
-
center in a parabolic quantum well are inves-tigated. The study has taken the effect of bulk longitudinal optical (LO) phonons into account. In order to simplify the calculation
we use the simple trial function for both electrons. By using the method of modified Lee-Low-Pines(LLP) variational method
the polarization potential and the ground state energy of D
-
center in the GaAs/Al
x
Ga
1-x
As PQW are obtained. The contribution of the impurity and LO phonon interaction to the total electron energy can be eliminated by the first canonical transformation
and the effect of this displacement on the lattice polarization leads to the polarization potential which partially compensates the electron-impurity Coulomb interaction. By the second canonical transformation
the ground state energy of the D
-
center in the infinite parabolic quantum well is worked out
and then the binding energy of D
-
center can be gained by further calculations. The research results indicate that
the ground state energy and binding energy of the D
-
center decreases rapidly with increasing
L
at the beginning
then decreases very slowly with increasing
L
and finally closes to the three-dimensional value in GaAs. Polaron effects on the properties of the D
-
center in a PQW were found to be important. Because the binding energy of the D
-
center is much smaller than that of a shallow donor
the relative contribution of the polaron correction is larger.
关键词
抛物量子阱极化子D-心
Keywords
parabolic quantum wellpolaronD- center
references
Riva C,Schweigert V A,Peeters F M.Off-center D- centers in a quantum well in the presence of a perpendicular magnetic[J].Phys.Rev.B,1998,57(24):15392-15399.
Shi J M,Peeters F M,Devreese J T.D- states in GaAs/AlxGa1-xAs superlattices in a magnetic field[J].Phys.Rev.B,1995,51(12):7714-7724.
Phelps D E,Bajaj K K.Ground state energy of a D- ion in two-dimensional semiconductors[J].Phys.Rev.B,1983,27(8):4883-4886.
Larsen D M.Giant binding of D- centers in polar crystals[J].Phys.Rev.B,1981,23(2):628-632.
Huant S,Najda S P.Two-dimensions D- centers[J].Phys.Rev.Lett.,1990,65(12):1486-1488.
Pang T,Louie S G.Negative-donor centers in semiconductors and quantum well[J].Phys.Rev.Lett.,1990,65(13):1635-1640.
German A,Luna-Acosta.Hydrogenic impurities in superlattices with parabolic quantum well potential[J].Solid State Commun.,1985,55(1):5-8.
Niculescu E C.Binding energy of a double donor in a parabolic quantum well[J].Phys.Lett.A,1995,197(4):330-334.
Niculescu E C.Donor impurity in a finite parabolic quantum well[J].Phys.Lett.A,1996,213(2):85-88.
Blinowski J,Szwacka T.Variational studies of D0 and D- centers in magnetic fields in bulk crystals and in parabolic quantum wells[J].Phys.Rev.B,1994,49(15):10231-10241.
Yuan Lihua,Wang Xu,An Zhanghui,et al.Polarization potential and the binding energy of a bound polaron in parabolic quantum well[J].Chin.J.Lumin.(发光学报),2005,26(6):709-713 (in Chinese).
Melnikov D V,Beall Fowier W.Bound polaron in a spherical quantum dot:Strong electron-phonon coupling case[J].Phys.Rev.B,2001,63(16):165302-1-8.
Platzman P M.Groun state energy of bound polarons[J].Phys.Rev.,1962,125(6):1961-1965.
Lee T D,Low F E,Pines D.The motion of slow electrons in a polar crystal[J].Phys.Rev.,1953,90(1):297-302.