Sommaire:

andau quantization has provided fascinating magnetotransport and magneto-optical phenomena in low-dimensional semiconductors. Due to progress in Terahertz (THz) techniques, high quality data on the magneto-optical effects have become available. Compared with cyclotron absorption experiments or THz photoresponse in resistivity, however, studies of the current-induced Landau-level (LL) emission are still difficult because of the requirement of ultrahigh sensitive detectors. In this talk, we briefly review THz photon counting techniques based on quantum dot (QD) detectors and show experimental results on the inter-LL radiative transition in quantum electron transport at strong magnetic fields.

Our approach for studies of LL emission is an on-chip THz photon detection scheme in which an emitter (an object: LL emitter), a photon counter (a QD) and a metal structure (that functions as a transmission or a resonator) are embedded in a single chip. We utilize a split-ring resonator for resolving photon energies of the LL emission. The energy-resolved photon-counting results indicate that, in violation of selection rules, the spin-flip LL radiative transition takes place in the spin-polarized edge channels. We will also discuss the exchange interaction and the spin-orbit interaction in the spin-polarized edge channels.

Pour plus d'informations, merci de contacter Chenaud B.