Estados eletrônicos de fios quânticos em bicamadas rotacionadas de semicondutores anisotrópicos bidimensionais

Abstract

Within the effective mass approximation, we theoretically investigate the confined electronic states in electrostatically defined quantum wires in a polarized and coupled rotated bilayer made of two-dimensional (2D) anisotropic semiconductor materials, i.e., materials with different effective masses along the x and y directions, and with the two layers being rotated relative to each other. Initially, we study the behavior of the energy bands of the infinite bilayer system as the following parameters are varied: (i) the rotation angle of the 2D bilayer system, (ii) the orientation of the applied magnetic field in the plane with respect to the crystallographic directions, (iii) the coupling term between the layers, and (iv) the application of electric and magnetic fields perpendicular to the system. Then, we investigate the behavior of an electrostatically defined quantum wire in a monolayer of anisotropic semiconductor material with arbitrary orientations relative to the crystallographic axes. Results for the electronic states (energy and wave functions) in the presence and absence of a magnetic field perpendicular to the plane are discussed and compared with recent work reported in the literature. We extend this analysis to the case of a magnetic field in the plane, aiming to discuss the bilayer case. Finally, analogous to the previous monolayer case, we investigate a system of quantum wires defined in a rotated bilayer of anisotropic semiconductors in the presence of external fields. We show that the orientation angle of the in-plane magnetic field acts as a control parameter, functioning as a modulator of anisotropy in the system, leading in some situations to the same energy results as the isotropic case. Furthermore, we find that the confined energy levels of the quantum wire and, consequently, the level spacing, are highly tunable with respect to the rotation angle and alignment orientation of the quantum wire.