The magneto-optics in quantum wires comprised of vertically stacked quantum dots: A calling for the magnetoplasmon qubits

Abstract

A deeper sense of advantages over the planar quantum dots and the foreseen applications in the single-electron devices and quantum computation have given vertically stacked quantum dots (VSQD) a width of interest. Here, we embark on the collective excitations in a quantum wire made-up of vertically stacked, self-assembled InAs/GaAs quantum dots in the presence of an applied magnetic field in the symmetric gauge. We compute and illustrate the influence of an applied magnetic field on the behavior characteristics of the density of states, Fermi energy, and collective (magnetoplasmon) excitations [obtained within the framework of random-phase approximation (RPA)]. The Fermi energy is observed to oscillate as a function of the Bloch vector. Remarkably, the intersubband single-particle continuum splits into two with a collective excitation propagating within the gap. This is attributed to the (orbital) quantum number owing to the applied magnetic field. Strikingly, the alteration in the well-and barrier-widths can enable us to customize the excitation spectrum in the desired energy range. These findings demonstrate, for the very first time, the viability and importance of studying the VSQD subjected to an applied magnetic field. The technological promise that emerges is the route to devices exploiting magnetoplasmon qubits as the potential option in designing quantum gates for the quantum communication networks. 78.20.Ls

Single-particle and collective excitations in quantum wires comprised of vertically stacked quantum dots: Finite magnetic field

“…For the illustrative numerical examples, we focus on the InAs/GaAs system just as in the original experiments [4][5][6]. The material parameters used are [85]: effective mass m * = 0.042m 0 (0.067m 0 ) and the background dielectric constant ǫ b = 13.9 (12.8) for the InAs (GaAs). We employ the potential barrier of height V 0 = 349.11 meV that produces the bandwidth (of the lowest (t = 0) miniband) W 0 = 19.76 meV, in compliance with Sakaki [2] so as to minimize the optical phonon scattering.…”

Magnetotransport in the quantum wires comprised of vertically stacked quantum dots

“…Specifically, it gives rise to a coherent acceleration of electrons which obviously boosts the chances of the Bloch oscillations, so acutely restrained in the conventional systems. This prognosis stimulated early experiments on the vertically stacked quantum dot (VSQD) systems in the mid-1990s (see, e.g., [8]). Subsequently, the anticipated device potential of the VSQD systems instigated many research groups with diverse research interests.…”