講演情報
[17p-K302-3]Chiral terahertz photocurrent in quantum point contact/quantum dot-split ring resonator coupled systems in the quantum Hall regime
〇(D)Jing Huang1, Kazuyuki Kuroyama1, Jinkwan Kwoen1, Yasuhiko Arakawa1, Kazuhiko Hirakawa1 (1.Univ. of Tokyo)
キーワード：
photocurrent measurement、cyclotron excitation、magnetoplasmon
Detection of ultrastrong coherent light-matter interaction by photocurrent measurements was realized recently, which provides new ways for investigating polariton physics and quantum transport in cavity fields. The physical processes underlying this electrical detection method, however, have not been fully understood yet. Particularly, the properties and origins of the photocurrent in the ultrastrong coupling regime remain elusive. In this work, we have investigated the terahertz (THz)-induced photocurrent in a coupled system of the quantum Hall edge electrons and THz photons in a split-ring resonator. The energy dispersion of the coupled system was measured by conducting THz-induced photocurrent spectroscopy through a quantum point contact (QPC). The dependence of the THz photocurrent on the polarities of a source-drain bias voltage and a magnetic field was systematically measured. We have found that the observed photocurrent is chiral in nature, showing that the behavior of the photocurrent is consistent with nonequilibrium edge channel transport due to generation and relaxation of Landau polaritons in multiple Landau levels. Furthermore, we point out that the QPC serves as an enhancer for the photocurrent signals. In addition, by replacing QPC with gate-defined quantum dot, different magneto-plasmon modes can also be detected, indicating the higher sensitivity of the electrical detection compared to the optical transmission measurement.