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We present results on non-local terahertz photoconductivity in Hg 1-x Cd x Te thick epitaxial films with the inverted energy spectrum $(\mathrm{x}\lt \sim 0.16)$. We show that the phototransport features observed in magnetic field indicate realization of the nonlocal electron transport regime, which is inherent to 2D topological insulators. We discuss the results in terms of a qualitative model that takes into account coexistence of the bulk transport and boundary conductive channels.

In this work, we demonstrate that the terahertz photoconductivity in Hg 1-x Cd x Te epitaxial films (x < 0.15) is featured by superimposed positive and negative components. The dramatic drop of the positive photoresponse as the sample thickness decreases indicates that the bulk-related processes crucially contribute to the non-equilibrium transport. At the same time, the features observed in magnetic field provide us with arguments for an edge transport channel formation. We discuss the sign-alternating photoconductivity kinetics in terms of a model that takes into account both the bulk electron excitation and the surface/interface state contribution.

We show that the terahertz photoconductivity in Hg 1-x Cd x Te-based films with the inversed band structure corresponding to the topological phase is asymmetric in magnetic field which may be considered as a T-symmetry breaking. Beside that, the photoconductivity is asymmetric for two mirror-symmetric pairs of potential probes which may be treated as a P- symmetry breaking. At the same time, the photoconductivity remains intact upon simultaneous swapping of both magnetic field and potential probe couple revealing thus the PT-symmetry.