In this talk, I will describe the in-plane photoelectric effect. This is a recently discovered quantum phenomenon  in a gated 2D electron gas (2DEG) that enables efficient terahertz detection. In this effect, electrons absorb THz photons and “jump” on an artificially created, electrically tunable potential step within the plane of a degenerate 2DEG. The effect is realized in photoelectric tunable-step (PETS) detectors – a new type of dual-gated field-effect transistor-type THz detectors with two antenna-shaped gates on top of a semiconductor heterostructure. The devices demonstrate a strong direct terahertz photoresponse at zero source-drain bias. It was found that previously known mechanisms were unable to explain the observed photoresponse, e.g., the observed photoresponse is an order of magnitude larger than expected from classical plasmonic mixing. We show that the observed photoresponse can be explained by a quantum mechanism that we call the in-plane photoelectric effect. We developed a theory  of the phenomenon, which describes the experimental data very well and predicts that this new mechanism is ideally suited for detection of radiation across the entire THz gap. We demonstrate key advantages of the 2D IPPE effect compared to the conventional, 3D photoelectric effect, and also present our latest theoretical results on the IPPE effect in a quasi-1D-electron system.
 W. Michailow et al., “An in-plane photoelectric effect in two-dimensional electron systems for terahertz detection”, Science Advances 8, eabi8398 (2022).
 S. A. Mikhailov, W. Michailow et al., “Theory of the in-plane photoelectric effect in two-dimensional electron systems”, Physical Review B 106, 075411 (2022)