The exact exchange potential in time-dependent density-functional theory is defined as an orbital functional through the time-dependent optimized effective potential (TDOEP) method. We numerically solve the TDOEP integral equation for the real-time nonlinear intersubband electron dynamics in a semiconductor quantum well with two occupied subbands. It is found that memory effects become signific...

Abstract Van der Waals heterostructures obtained by artificially stacking two-dimensional crystals represent the frontier of material engineering, demonstrating properties superior to those starting materials. Fine control interlayer twist angle has opened new possibilities for tailoring optoelectronic these heterostructures. Twisted bilayer graphene with a strong coupling is prototype twisted ...

We show the formation of bright and dark slow optical solitons based on intersubband transitions in a semiconductor quantum well (SQW). Using the coupled Schrödinger-Maxwell approach, we provide both analytical and numerical results. Such a nonlinear optical process may be used for the control technology of optical delay lines and optical buffers in the SQW solid-state system. With appropriate ...

The design of terahertz quantum cascade lasers based on electronic intersubband transitions in Ge/SiGe quantum wells is investigated. A detailed theoretical model of the conduction-band lineup of these heterostructures is first presented and used to show that large quantum confinement in the L valleys can be obtained with properly selected layer compositions and thicknesses. Computation of the ...