Impurity-related intraband absorption in coupled quantum dot-ring structure under lateral electric field

Abstract

Impurity-related intraband absorption in coupled quantum dot-ring structure under lateral electric field, Physica E: Low-dimensional Systems and Nanostructures, http://dx.doi.org/10. 1016/j.physe.2015.07.032 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.www.elsevier.com/locate/physe Impurity-related intraband absorption in coupled quantum dot-ring structure under lateral electric field AbstractThe effects of a lateral electric field on intraband absorption in GaAs/GaAlAs two-dimensional coupled quantum dot-ring structure with an on-centre hydrogenic donor impurity is investigated. The confining potential of the system consists of two parabolas with various confinement energies. The calculations are made using the exact diagonalization technique. A selection rule for intraband transitions was found for x-polarized incident light. The absorption spectrum mainly exhibits a redshift with the increment of electric field strength. On the other hand, the absorption spectrum can exhibit either a blue-or redshift depending on the values of confinement energies of dot and ring. Additionally, electric field changes the energetic shift direction influenced by the variation of barrier thickness of the structure.

Influence of lateral electric field on intraband optical absorption in concentric double quantum rings

“…If R 1 = 0 we have dot-ring structure, with a QR of a radius R 2 , the model of which based on Eq. 1 was studied in [25,26,33]. Note that the initial enlargement of R 1 makes the inner ring, thus creating wider confinement potential.…”

“…The confinement is affected by the lateral electric field directed in the x-axis as shown in Fig.1. Note that in the limit R 1 → 0 the potential is reduced to one of a central QD encircled with QR of a radius R 2 [25,26,33], while in the case of R 1 = R 2 = R the model is reduced to a single ring structure [1,22]. The general form of the potential (1) has been used in Refs.…”

“…We remark that this technique is a useful numerical method to compute the eigenstates of quantum systems [38,39]. In particular, it has been employed in QDs [40], in QRs [24,41] as well as in CQDR structures [26,42]. In addition, let us comment that in Ref.…”

“…In the past decade, a number of works were devoted to the theoretical investigation of the influence of electric fields on the electronic and optical properties of QR structures [16][17][18][19][20][21][22][23][24][25][26][27][28]. For instance, in Ref.…”

“…This study shewed that the influence of lateral electric field on energy levels strongly depends on the electron localization type. The investigations of intraband transitions in CQDR [26] demonstrated that lateral electric field changes energetic shift direction influenced by the variation of barrier thickness of the structure.…”