Abstract-Magnetopolaron effect on shallow-impurity states in the presence of magnetic and intense terahertz laser fields in the Faraday configuration

Weiyang Wang, B. Van Duppen, M. Van der Donck, and F. M. Peeters

https://journals.aps.org/prb/accepted/6d07dO43Z4211c3b81984d103a35761924e4abf57

The magnetopolaron effect on shallow-impurity states in semiconductors is investigated when subjected simultaneously to a magnetic field and an intense terahertz laser field within the Faraday configuration. We use a time-dependent non-perturbative theory to describe electron interactions. The externally applied fields are exactly included via a laser-dressed interaction potential. Through a variational approach we evaluate the binding energy of the shallow-impurity states. We find that the interaction strength of the laser-dressed Coulomb potential can not only be enhanced but also weakened by varying the two external fields. In this way the binding energy can be tuned by the external fields and red- or blue-shifted with respect to the static binding energy. In the nonresonant polaron region, a novel magnetopolaron correction that includes the effects of photon process is observed. In the resonant polaron region, moreover, the resonant {\color{black}magnetopolaron} effect accompanied by the emission and absorption of a single photon is distinctly observed. This can be modulated to be far away from the reststrahlen band. The intriguing findings of this manuscript can be observed experimentally and, in turn, provide a new way to measure the strength of the electron-phonon interaction.

Abstract-Effect of intense terahertz laser and magnetic fields on the binding energy and the transition energy of shallow impurity in a bulk semiconductor

Weiyang Wang,  Lei Xu, Bo Wu, Sha Zhang, Xiangfei Wei

http://www.sciencedirect.com/science/article/pii/S092145261730368X

The influences of intense terahertz laser and magnetic fields on shallow-donor states in GaAs bulk semiconductors in the Faraday geometry are studied theoretically in the framework of the effective-mass approximation. The interaction between the laser field and the semiconductor is treated nonperturbatively by solving analytically the time-dependent Schrödinger equation in which the two external fields are included exactly. In the nonresonant region, we have found that the binding and transition energies decrease with increasing laser-field intensity or decreasing laser-field frequency, and the binding energy increases with magnetic field. For relatively low radiation levels, the transition energy first slowly decreases with increasing magnetic field, but after a critical value, it rapidly increases with increasing magnetic field. However, it slowly decreases with magnetic field when the laser-field intensity is strong enough. Furthermore, in the vicinity of the resonant regime, the oscillatory behaviours of the binding and transition energies with laser-field frequency and magnetic field are observed. These results obtained indicate the possibility of manipulating the shallow impurity states in semiconductor by changing the intense laser-field frequency and intensity and the magnetic field, which gives a new degree of freedom in semiconductor device application.