Impurity magnetopolaron in a parabolic quantum dot: the squeezed-state variational approach

Abstract

We present a calculation of the ground-state binding energy of an impurity magnetopolaron confined in a three-dimensional (3D) parabolic quantum dot potential, in the framework of a variational approach based on two successive canonical transformations. First, we apply a displaced-oscillator type unitary transformation to diagonalize the relevant Fröhlich Hamiltonian. Second, a single-mode squeezed-state transformation is introduced to deal with bilinear terms arising from the first transformation. Finally, the parameters of these transformations together with the parameters included in the electronic trial wavefunction are determined variationally to obtain the ground-state binding energy of an impurity magnetopolaron confined in a 3D parabolic quantum dot potential. Our approach has two advantages: first, the displaced-oscillator transformation allows one to obtain results valid for whole range of electronphonon coupling strength since it is a special combination of Lee-Low-Pines and Huybrechts (LLP-H) canonical transformations, and second, the later transformation improves all-coupling results. It has been shown that the effects of quadratic terms arising from the all-coupling approach are very important and should be taken into account in studying the size-dependent physical properties of nanostructured materials.

Decoherence of Polaron in Asymmetric Quantum Dot Qubit Under an Electromagnetic Field

“…The magnetic field enhances electron-phonon interaction and can thus be considered as a new confinement of the electron. As the magnetic field increases, the electron moves away from the center and gets closer to the surface along the axis, resulting in the contribution of the bulk LO phonon to the reduction of the ground state energy which is experimentally very important for the control and modulation of the intensity of optoelectronic devices [28][29][30][31][32]. This plot shows that the spontaneous emission rate increases with the increase of the cyclotron frequency and decreases with the increases of the electron-phonon coupling constant.…”

Influences of RSO interaction and LO phonon effect on the spin polarization state energy of polaron in a quantum rod

“…In the recent times, the physical properties of low dimensional semiconductor nanostructures such as quantum dot (QD), quantum-well wire (QWW), quantum ring (QR), quantum rod (QRD) have been received considerable attention due to their novel physical properties and their appealing potential industrial applications [1][2][3][4][5][6]. Up to now, a great number of theoretical works have been done [7][8][9][10] because the studies on the electronical and optical properties in QRD are important in exploring new photo electric properties, transport properties and application properties.…”

Bound polaron in a two- and three-dimensional quantum dot for arbitrary electron–phonon coupling strength

“…In addition, the polaronic effect increases quite considerably with the decreasing size of the QD. Because impurities have a great influence on the optical and transport properties of the materials, special attention has been paid to the impurity state and bound polaron, taking electron-LO phonon interaction into consideration [10][11][12][13][14][15][16][17][18][19]. Xie and Chen have investigated the phonon contribution to the binding energy of the on-center and off-center impurities in a spherical QD [10].…”

“…An analogous problem by the Lee-Low-Pines-Bogolubov canonical transformation method has also been investigated in Ref. [15]. The multidimensional polaron problem introduced by Peeters, Wu, and Devreese [20] (PWD) has generated a great deal of interest.…”