Effects of confined longitudinal optical phonons on the binding energy of the impurity in a quantum well

Abstract

The effects of the confined LO phonon-electron interaction on the binding energy of shallow donors confined in a GaAs-Gal -,Al,As quantum well are investigated. The barrier potential height is taken into account. Using the variational method of Lee-Low-Pines, we find that the effect of this interaction is negligible for very narrow quantum wells. For thick quantum wells, the polaronic contribution is quite large.

Impurity Binding Energy in Polar Quantum Dot with Finite Potential Barriers

“…As expected, the values of the impurity binding energies are higher in the case of quasi-zero-dimensional QDs than in the quasi-one-and -two-dimensional systems (QWWs and QWs) [8][9][10]16]. The binding energies obtained in this work, in the region where the dot size is larger than a * , are in agreement with those obtained previously with an infinite potential well in the absence [9] and in the presence of confined LO-phonon effect [13].…”

“…Over the past decades, most of the body of the experimental and theoretical work on the properties of impurities in semiconductor structures has already been carried out and has been devoted to the study of the electronic state in these microstructures [1][2][3][4][5][6][7][8][9]. As the situation of a hydrogenic impurity embedded in quantum dot has no exact solution it has been studied by the variational method, the effective mass approximation, the first-principles method, the effective bound-orbital model, the tight-binding self-consistent linear screening calculation, the plane wave semi-empirical pseudo-potential method with non-local potential and the Feynman-Haken method [10][11][12][13][14][15][16][17][18][19][20]. The binding energies and the density of states of shallow impurities in a cubic [9] and in a spherical quantum dot [8,12] have been calculated as function of the dot size and the impurity position in the quantum dot.…”

Layer-Dependent Coherent Acoustic Phonons in Two-Dimensional Ruddlesden–Popper Perovskite Crystals

“…The TR signal of (PEA)2PbI4 decays faster than that of (EA)2PbI4 (1.5 ps vs. 5.5 ps) since the larger exciton binding energy of the PEA-linked 2D crystal promotes the release of the LO at a faster rate. [35][36] Therefore, the slower LO phonon emission rate with increasing number of inorganic layers is due to decreased exciton binding energy. 37,38 The observed TR oscillation can be attributed to the propagation of the coherent longitudinal acoustic phonons (CLAPs) inside the crystal lattice.…”

“…At very early delays, the photoinduced TR signal of the 2D RP perovskite crystals decays with an average time of 1.5–8 ps, which can be attributed to the relaxation of the hot carriers associated with LO phonons. The TR signal of (PEA) 2 PbI 4 decays faster than that of (EA) 2 PbI 4 (1.5 ps vs 5.5 ps) because the larger exciton binding energy of the PEA-linked 2D crystal promotes the release of the LO at a faster rate. , Therefore, the slower LO phonon emission rate with increasing number of inorganic layers is due to decreased exciton binding energy. , The observed TR oscillation can be attributed to the propagation of the CLAPs inside of the crystal lattice. ,,, The amplitude difference of the TR signal is due to the relative contribution of the thermoelastic properties and the deformation potential (DP) values of the perovskite crystals …”

Electron-confined longitudinal optical phonon interaction and strong magnetic field effects on the binding energy in GaAs quantum wells

“…Licari and Evrard 9 gave a Hamiltonian for the electronphonon interaction in a polar crystal slab. Since, then, a considerable number of articles regarding the coupling of a Q2D electron system with optical phonons have been published [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] both with and without considering magnetic field effect.…”