THz field, absolute negative conductance and formation of domains in semiconductor superlattices

摘要

Electrons in a semiconductor superlattice interact most effectively with electromagnetic fields of THz frequency domain. It is known that a formation of high field and low field domains can strongly alter nonlinear properties of nanostructures at THz frequencies. However, existing theories of THz-induced nonlinear phenomena in superlattices are based on an assumption of spatially homogeneous field distribution inside superlattice and, therefore, they do not take into account a possibility of domain formation. In this report, we examine the necessary conditions for domains build up under the action of strong THz field. We show that a number of nonlinear processes, arising in semiconductor superlattices under the action of strong THz field, should be influenced by the domains. Our theoretical work is relevant to several experimental activities.