Rotating effects on the photoionization cross-section of a 2D quantum ring

TL;DR

The paper analyzes how rotation in a 2D quantum ring with Aharonov-Bohm flux and a uniform magnetic field affects photoionization cross-section (PCS). Using the Tan–Inkson model in a rotating frame, it derives the $H_{\Omega}$ Hamiltonian, reduces to a radial equation, and obtains analytic eigenfunctions $\psi_{nm}$ and energies $E_{nm}$, with a selection rule $\Delta m=\pm 1$ for dipole transitions. The PCS is computed via Fermi’s golden rule in the dipole approximation, including a Lorentzian broadening, and numerical results for GaAs demonstrates how AB flux $\phi$ and rotation $\Omega$ tune PCS peak amplitudes and positions for the two lowest transitions. The findings show strong control of the optical response by rotation and AB flux, offering insights for designing quantum-ring-based optoelectronic devices.

Abstract

In this letter, we investigate the nonrelativistic quantum motion of a charged particle within a rotating frame, taking into account the Aharonov-Bohm (AB) effect and a uniform magnetic field. Our analysis entails the derivation of the equation of motion and the corresponding radial equation to describe the system. Solving the resulting radial equation enables us to determine the eigenvalues and eigenfunctions, providing a clear expression for the energy levels. Furthermore, our numerical analysis highlights the substantial influence of rotation on both energy levels and optical properties. Specifically, we evaluate the photoionization cross-section (PCS) with and without the effects of rotation. To elucidate the impact of rotation on the photoionization process of the system, we present graphics that offer an appealing visualization of the intrinsic nature of the physics involved.

Figures (3)

• Figure 1: Graphs illustrating the PCS as a function of photon energy for various values of the average radius $r_{0}$, with a fixed value of $\hbar\omega_{0}=25\, \text{meV}$. The graphs specifically depict the transition (${n=0, m=0}$) to (${n=0, m=-1}$), where (a) corresponds to $\Omega= 0$ and (b) corresponds to $\Omega= 1\, \text{THz}$. The bluish region with solid curves corresponds to a fixed value of the magnetic flux, $\phi=0.1\, (hc/e)$, and the dashed curves outside this region represent the value of magnetic flux $\phi=0.8\, (hc/e)$.
• Figure 2: The same graphs as those in Fig. \ref{['fig:flux']}, representing the transition (${n=0, m=0}$) to (${n=0, m=1}$). (a) Corresponds to $\Omega= 0$, and (b) corresponds to $\Omega= 1\, \text{THz}$. The bluish region with solid curves corresponds to a fixed value of the magnetic flux, $\phi=0.3\, (hc/e)$, while the dashed curves outside this region represent the value of magnetic flux $\phi=0.01\, (hc/e)$.
• Figure 3: Graphs of the PCS for different values of the rotating parameter. We have fixed the values of $r_{0}=12\, \text{nm}$ and $\hbar\omega_{0}=25\, \text{meV}$, magnetic flux $\phi=0.1\, (hc/e)$. (a) For the transition (${n=0,m=0}$) to (${n=0,m=-1}$) and (b) for the transition (${n=0,m=0}$) to (${n=0,m=1}$).