Available online at www.sciencedirect.com Physica E 20 (2004) 286–289 www.elsevier.com/locate/physe Zeeman eect and magnetic anomalies in narrow-gap semiconductor quantum dots S.J. Prado a ; * , C. Trallero-Giner b ,V.L opez-Richard c , A.M. Alcalde a , G.E. Marques a a Departamento de F sica, Universidade Federal de S˜ ao Carlos, S˜ ao Carlos, SP 13565-905, Brazil b Department of Theoretical Physics, Havana University, San Lazaro, Habana 10400, Cuba c Instituto de F sica de S˜ ao Carlos, Universidade de S˜ ao Paulo, S˜ ao Carlos, SP 13560-970, Brazil Abstract We present a systematic theoretical study, based on the Kane–Weiler 8 × 8 k · p model, of the linear Zeeman splitting introduced by the interaction between the angular momentum and the magnetic eld which can give a measure of the non-linear Zeeman eect associated with interband coupling and diamagnetic contributions. The conduction and valence bands g-factors are calculated for InSb spherical and semi-spherical quantum dots. The calculations of the g-factors showed an almost linear dependence, for the ground state, on the magnetic eld. We have also found that the strong magnetic eld dependence as well as the dependence on the dot size of the eective spin splitting can be unambiguously attributed to the strength of the inter-level mixing. ? 2003 Elsevier B.V. All rights reserved. PACS: 71.70.Ej; 73.21.La Keywords: Quantum dots; Zeeman splitting 1. Introduction A precise knowledge of the eective Land e g-factors is required for the interpretation of magneto-optical experiments, magneto-transport phe- nomena, resonant spectroscopy and spin-ip inelastic light scattering. The analysis of the Zeeman splitting associated to the Land e factors and its magnetic tun- ing allows for a better understanding of spin eects on the optical response of the low-dimensional systems. The eective g-factor in low-dimensional systems ∗ Corresponding author. Tel.: +55-16-260-8205; fax: +55-16- 261-4835. E-mail address: psprado@df.ufscar.br (S.J. Prado). has attracted an increasing interest of theoreticians and experimentalists [1,2] due to the possibility of spin manipulation in semiconductors for applications on spin-polarized magneto-electronics and quantum computation that require some control on the time and length scales of the spin coherency [3]. The values of the g-factor are closely related to the semi- conductor band parameters and to the connement conditions. Thus, electron and hole carriers in semi- conductor nanostructures may display values with strong deviations from its bulk values. By consider- ing a single InSb spherical (SQD) and semi-spherical quantum dots (SSQD), we will analyze: (i) the linear Zeeman splitting introduced by the interaction be- tween the angular momentum and the magnetic eld, (ii) the non-linear Zeeman eect associated with 1386-9477/$ - see front matter ? 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.physe.2003.08.020