Positive terahertz photoconductivity is observed at room temperature in CdHgTe thin films with different Cd contents. We show that electron gas heating caused by Drude-like absorption results in positive photoconductivity because of the interband activation mechanism specific for undoped narrow-gap semiconductors and semimetals. Applying intense terahertz radiation, we observed that the photoconductivity saturates at high intensities, which was found to be caused by absorption bleaching. Both the magnitude of the photoconductivity and the saturation intensity are shown to exhibit an exponential dependence on the hydrostatic pressure. We show that this is a consequence of the fact that both phenomena are controlled by the ratio of energy and momentum relaxation times.
@article{arxiv.2504.08319,
title = {Positive Terahertz Photoconductivity in CdHgTe Under Hydrostatic Pressure},
author = {Ivan Yahniuk and Dmitriy A. Kozlov and Mariya D. Moldavskaya and Leonid E. Golub and Vasily V. Bel'kov and Ivan A. Dmitriev and Sergey S. Krishtopenko and Frederic Teppe and Yurii Ivonyak and Artem Bercha and Grzegorz Cywiński and Wojciech Knap and Sergey D. Ganichev},
journal= {arXiv preprint arXiv:2504.08319},
year = {2025}
}