Terahertzstrahleninduzierter Quantentransport in Halbleiter-Nanostrukturen
Zusammenfassung der Projektergebnisse
This project aimed to get insight into the origin of photocurrents and photoconductivity excited by terahertz radiation in semiconductor heterostructures in the regime of quantum magnetooscillations. This includes MIRO-like oscillations and 1/B periodic oscillations of the photocurrent and photoconductivity at cyclotron resonance condition. We explored several novel phenomena excited in various two-dimensional systems and obtained a multifaceted picture of THz-induced magneto-transport. To the most important results belong the observations that (i) TIRO are excited in the material bulk and not at the edges; (ii) TIRO have a weak sample-dependent sensitivity on the radiation helicity; (iii) TIRO are nonlinear as a function of the radiation intensity; (iv) TIRO occur also in HgTe-based QWS; (v) signalternating oscillations of the photoconductivity occur in HgTe QWs; and (iv) magnetooscillations of the photocurrent in graphene are to coupled to the harmonics of the cyclotron resonance. Furthermore, our results demonstrated that in the THz range magneto-oscillations can be detected at much lower mobilities of the 2DES as compared to the microwave counterpart. Further, the crucial condition for TIRO to occur is ω > τq-1, where τq is the quantum time. Our results are supported by theoretical models, which describe the experimental findings well. To the unexpected results belongs the observation of 1/B periodic oscillations of the photocurrent. In the original proposal, experiments on graphene were not planned because one needs extraordinarily large-size and high-quality graphene structures to detect and study the magneto-oscillation linked to cyclotron resonance. Such structures, fabricated by the MIT group of Dr. Denis Bandurin, we obtained during the final stage of the project. As a result, we very recently uncovered different kinds of terahertz radiation-driven phenomena, which are observed in graphene for the first time. Our work showed that the oscillations emerge in graphene even at high frequencies and, quite remarkably, persist above liquid nitrogen temperatures. Moreover, their fundamental frequency is tunable by a gate voltage. These surprising observations demonstrate the unique features of THz-induced magnetotransport in graphene, yield novel experimental access to plasmonic and hydrodynamic phenomena, and pave the way for a deeper understanding of the rich spectra of nonequilibrium phenomena in Dirac fermion systems.
Projektbezogene Publikationen (Auswahl)
- Magneto-resistance oscillations induced by high-intensity terahertz radiation, Phys. Rev. B 96, 115449 (2017)
T. Herrmann, Z. D. Kvon, I. A. Dmitriev, D. A. Kozlov, B. Jentzsch, M. Schneider, L. Schell, V. V. Bel'kov, A. Bayer, D. Schuh, D. Bougeard, T. Kuczmik, M. Oltscher, D. Weiss, and S. D. Ganichev
(Siehe online unter https://doi.org/10.1103/PhysRevB.96.115449) - Signalternating photoconductivity and magnetoresistance oscillations induced by terahertz radiation in HgTe quantum wells, Phys. Rev. B 98, 245304 (2018)
M. Otteneder, I. A. Dmitriev, S. Candussio, M. L. Savchenko, D. A. Kozlov, V. V. Bel'kov, Z. D. Kvon, N. N. Mikhailov, S. A. Dvoretsky, and S. D. Ganichev
(Siehe online unter https://doi.org/10.1103/PhysRevB.98.245304) - Terahertz Laser Radiation Induced Resistivity Oscillations in GaAs Heterostructures, Uni Regensburg, PhD thesis (2019)
T. Hermann
- Microwave response of interacting oxide two-dimensional electron systems, Phys. Rev. B 102, 115432 (2020)
D. Tabrea, I. A. Dmitriev, S. I. Dorozhkin, B. P. Gorshunov, A. V. Boris, Y. Kozuka, A. Tsukazaki, M. Kawasaki, K. von Klitzing, and J. Falson
(Siehe online unter https://doi.org/10.1103/PhysRevB.102.115432) - Observation of terahertz-induced magnetooscillations in graphene, Nano Lett. 20, 5943 (2020)
E. Mönch, D. A. Bandurin, I. A. Dmitriev, I.Y. Phinney, I. Yahniuk, T. Taniguchi, K. Watanabe, P. Jarillo-Herrero, and S. D. Ganichev
(Siehe online unter https://doi.org/10.1021/acs.nanolett.0c01918) - High Harmonics of the Cyclotron Resonance in Microwave Transmission of a High-Mobility Two-Dimensional Electron System, Phys. Rev. Research 3, L012013 (2021)
M. L. Savchenko, A. Shuvaev, I. A. Dmitriev, A. A. Bykov, A. K. Bakarov, Z. D. Kvon, and A. Pimenov
(Siehe online unter https://doi.org/10.1103/PhysRevResearch.3.L012013)
