Roles of Elements of a Heterostructure Based on the Topological Phase of Hg 1 – x Cd x Te in the Effect of PT -Symmetric Terahertz Photoconductivity

It is demonstrated that the PT -symmetric terahertz photoconductivity observed in heterostructures based on thick Hg 1 – x Cd x Te films in the topological phase is due to the photoexcitation of charge carriers in the film bulk. At the same time, the place of localization of the effect is the topological film–trivial buffer layer heterointerface. The model describing such a spatial separation of the source of nonequilibrium charge carriers and the effect localization is discussed.