Available online at www.sciencedirect.com Physica E 22 (2004) 860–866 www.elsevier.com/locate/physe Direct interband light absorption in a cylindrical quantum dot in quantizing magnetic eld M.S. Atoyan, E.M. Kazaryan, H.A. Sarkisyan * Department of Physics, Yerevan State University, Al. Manoukyan Street 1, Yerevan 375025, Armenia Received 17 September 2003; accepted 23 September 2003 Abstract In this paper the direct interband transitions in cylindrical quantum dot (QD) made of GaAs are studied in the presence of a magnetic eld. Two models of QD connement potential are discussed. For both models the expressions for absorption coecients and dependencies of eective threshold frequencies of absorption on the value of applied magnetic eld and on geometrical sizes of QD are obtained. The selection rules corresponding to dierent transitions between quantum levels are found. ? 2003 Elsevier B.V. All rights reserved. PACS: 71.20.Nr; 73.61Ey Keywords: Absorption coecient; Quantum dot; Magnetic eld 1. Introduction One of the most intensively explored classes of size-quantized (SQ) semiconductors is the class of zero-dimensional structures (the so-called quantum dots (QD)). The peculiar property of these systems is their ability for complete quantization of energy spec- trum of charge carriers (CC) in them. This results in -shaped character of CC density of states. Therefore, it is possible to expect that the peculiar properties of QD behavior will strongly dier from those of one-dimensional and two-dimensional systems [1]. A strong dependence of the energy spectrum of CC on the geometrical shape and sizes of QD allows to manipulate the energy spectrum and consequently, ∗ Corresponding author. Fax: 374-1-55-4641. E-mail address: shayk@www.physdep.r.am (H.A. Sarkisyan). the physical characteristics of QD as well, during the growth of a concrete sample. In other words, these arises a unique opportunity to derive structures with the physical characteristics given beforehand [2]. In particular, study of optical absorption in QD has shown that it is possible to change the threshold fre- quencies of absorption changing the sizes and shapes of QD [3]. The optical properties of QD for the rst time were considered by Efros and Efros [4] at theoretical in- vestigation of direct light absorption in spherical QD with indenitely high walls. The analytical dependen- cies of threshold frequencies of absorption on QD ra- dius and the appropriate selection rules by quantum numbers were obtained for transitions from one state to another. Then Andreev and Lipovskii [5] discussed the inuence of anisotropy of band structure on op- tical transitions in spherical QDs. It was shown that 1386-9477/$ - see front matter ? 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.physe.2003.09.042