Diamagnetic susceptibility: An indicator of pressure induced donor localization in a double quantum well G. Vignesh, P. Nithiananthi * Nanostructure Lab, Department of Physics, Gandhigram Rural University, Gandhigram, 624 302, Tamilnadu, India article info Article history: Received 29 October 2015 Received in revised form 10 February 2016 Accepted 11 February 2016 Available online 16 February 2016 Keywords: Double quantum well Diamagnetic susceptibility Hydrostatic pressure Electron-donor distance abstract The influence of pressure along the growth axis on carrier localization in GaAs/Al 0.3 Ga 0.7 As Double Quantum Well (DQW) is studied under strongly coupled regime and isolated re- gimes of the well. The effective mass approximation combined with variation technique is adopted with the inclusion of mismatches in effective mass and dielectric constants of the well and barrier material. Effect of the barrier and well on carrier localization is investi- gated by observing the diamagnetic susceptibility (c dia ) for various impurity locations (z i ) and the critical limit of the barrier (L b z 50 Å) for tunneling has also been estimated. The effect of G-Х crossover due to the application of pressure on the donor localization is picturized through diamagnetic susceptibility. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Existence of unique properties and survival of effective mass approximation for systems in ground state have made the semiconductor nanostructure an interesting material to explore until now. Semiconductor Quantum Heterostructures have been an interesting paradigm, whose physical properties are explored by solving an Eigen equation of a charged particle confined in such systems [1e5]. Towards this search, Double Quantum Wells (DQW) with various barrier frames and perturbations have been exploited to familiarize the physics of carriers inside it [6e8]. The quasi bound states in DQW can be tuned by altering the barriers or by any external perturbation which bring out resonant tunneling of electrons. These properties are exploited in generation and detection of ultrahigh frequency (terahertz) electromagnetic oscillations [9], fabricating low loss waveguides [1] etc. Asymmetric DQW are more preferable for such applications since they provide different resonant tunneling in each well. Comparing to a single QW with double barrier structure, DQW/Multiple QW (MQW) with triple barrier may regulate the resonant tunneling [7] effectively, whenever there is a resonance matching within the subband. There is voluminous literature on DQW associated with perturbations which are useful in fabricating optoelectronic devices and to study many body and nonlinear effects. Pressure has been recognized as a versatile tool for regenerative band structure tuning of nanostructures. As a primary effect applied pressure increases the carrier effective mass, reduces the dielectric constants, squeezes the well and changes the effective Rydberg of the respective layers. As a secondary effect, application of pressure induces hybridization of G and Хelike Bloch states [10] in narrow wells. This effect is observed in photoluminescence spectra and is visible in resonant tunneling and magneto-optical measurements such as Far Infrared (FIR) Magneto spectroscopy. In GaAs/Al 0.3 Ga 0.7 As QW, as pressure grows, lack of translational symmetry along * Corresponding author. E-mail address: nithyauniq@gmail.com (P. Nithiananthi). Contents lists available at ScienceDirect Superlattices and Microstructures journal homepage: www.elsevier.com/locate/superlattices http://dx.doi.org/10.1016/j.spmi.2016.02.017 0749-6036/© 2016 Elsevier Ltd. All rights reserved. Superlattices and Microstructures 92 (2016) 232e241