PT-Symmetric Terahertz Photoconductivity in Hg1-xCdxTe

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.