Wavefunction analysis and optical nutation in magnetized semiconductor quantum wires exhibiting multiple valence subbands

Abstract

The energy eigenvalues and eigenfunctions have been obtained for a GaAs/AlGaAs quantum wire structure with multiple valence subbands, subjected to an external magnetic field. The hole wavefunctions are calculated by numerical diagonalization of Luttinger Hamiltonian in an appropriately chosen basis. The electron -hole wavefunctions thus obtained are used in conjunction with effective semiconductor Bloch equations for the study of optical coherent transient effects like optical nutation. The results show squeezing of wavefunctions with increasing magnetic field while band mixing effects lead to overlapping of peaks. The corresponding optical nutation curves show an increase in nutation frequency with magnetic field while band mixing effects are revealed through multiple oscillations.

Optical nutation induced by transition between levels inside and outside the well in a core–shell CdSe/ZnS quantum dot

“…It is shown in figure 3 that the nutation signal decays rapidly: it arises due to the transient polarization induced in the QD and decays for the reason that the absorption coefficient is directly proportional to the population difference of the electrons, which is decreasing rapidly. Similar decay behaviour for quantum wires and micro-cavity was reported in [13,14,[23][24][25].…”

“…First, we have calculated the electric transition dipole moment induced by 1s (inside the well)-1s (outside the well) transition using equation (18) under the condition that μ ab = 5.101 × 10 −29 C m, R 1 = 4.5 nm and R 2 = 5.5 nm. The optical nutation signal is obtained from equations ( 23) and (24), and is shown in figure 3.…”