Terahertz‐induced effects on excitons in magnetic field

Abstract

Terahertz‐induced intra‐exciton transitions are studied in semiconductor quantum‐well systems under the influence of a constant magnetic field. A systematic description is developed to include carrier–carrier interactions, terahertz transitions, and magnetic‐field effects to the exciton‐correlation dynamics. When a magnetic field is present, the exciton states and energies are changed directly and parametrically via the center‐of‐mass momentum of excitons. The numerical results show that both effects influence the terahertz spectroscopy. Especially, the transition between 1s‐ and 2p‐exciton states is shown to depend strongly on both magnetic field and center‐of‐mass momentum. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Terahertz-induced exciton signatures in semiconductors

“…Especially, the magnetic field can be used to shift the different excitonic resonances and lift the degeneracy caused by p ‐like states. For the treatment of this problem, it is necessary to solve the generalized excitonic Wannier equation, i.e., the non‐Hermitian excitonic eigenvalue problem (), in the presence of a magnetic field, using the resulting eigenfunctions as basis ().…”

Magnetic control of Coulomb scattering and terahertz transitions among excitons

“…Magnetic field (T) ton dynamics [17,29] in the presence of THz and B-fields for all relevant bright and dark exciton states and compute the resulting PL via the Elliott formula. Figure 3 shows the computed −∆PL 1s [ Fig.…”

“…For our microscopic analysis, we start from the standard many-body Hamiltonian that includes the electronic band structure, the Coulomb interactions among the charge carriers, as well as the light-field and THz interactions [1,28]. To account for the B-field, we use the Hamiltonian [29]…”

“…The reduced mass (µ) and total mass (M ) enter together with the Coulomb interaction V (r), effective cyclotron frequencies ωj , where e and h denote electron and hole, respectively, and angular momentum operator Lz . We solve the exci- ton dynamics [17,29] in the presence of THz and B-fields for all relevant bright and dark exciton states and compute the resulting PL via the Elliott formula. Figure 3 shows the computed −∆PL 1s [Fig.…”