%0 Journal Article %J Applied Physics LettersApplied Physics LettersApplied Physics Letters %D 2008 %T Terahertz response of quantum point contacts %A Song, J. W. %A Kabir, N. A. %A Kawano, Y. %A Ishibashi, K. %A Aizin, G. R. %A Mourokh, L. %A Reno, J. L. %A Markelz, A. G. %A Bird, J. P. %K detector %K devices %K field-effect transistors %K Physics %K plasma-waves %K radiation %K resonant detection %K subterahertz %K transport %X

We measure a clear terahertz response in the low-temperature conductance of a quantum point contact at 1.4 and 2.5 THz. We show that this photoresponse does not arise from a heating effect, but that it is instead excellently described by a classical model of terahertz-induced gate-voltage rectification. This effect is distinct from the rectification mechanisms that have been studied previously, being determined by the phase-dependent interference of the source drain and gate voltage modulations induced by the terahertz field. (C) 2008 American Institute of Physics.

%B Applied Physics LettersApplied Physics LettersApplied Physics Letters %V 92 %P 3 %8 Jun %@ 0003-6951 %G English %9 Article %M WOS:000256527900083 %] 223115 %! Appl. Phys. Lett.Appl. Phys. Lett. %R https://doi.org/10.1063/1.2938416 %0 Journal Article %J Applied Physics Letters %D 2006 %T Terahertz transmission characteristics of high-mobility GaAs and InAs two-dimensional-electron-gas systems %A Kabir, N. A. %A Yoon, Y. %A Knab, J. R. %A Chen, J. Y. %A Markelz, A. G. %A Reno, J. L. %A Sadofyev, Y. %A Johnson, S. %A Zhang, Y. H. %A Bird, J. P. %K field-effect transistors %K photoconductivity %K Physics %K plasma-waves %K radiation %K resonant detection %K subterahertz %X

Frequency-dependent complex conductivity of high-mobility GaAs and InAs two-dimensional-electron-gas (2DEG) systems is studied by terahertz time domain spectroscopy. Determining the momentum relaxation time from a Drude model, the authors find a lower value than that from dc measurements, particularly at high frequencies/low temperatures. These deviations are consistent with the ratio tau(t)/tau(q,) where tau(q) is the full scattering time. This suggests that small-angle scattering leads to weaker heating of 2DEGs at low temperatures than expected from dc mobilit9y. (c) 2006 American Institute of Physics.

%B Applied Physics Letters %V 89 %P 3 %8 Sep %@ 0003-6951 %G English %9 Article %M WOS:000240875800066 %] 132109 %! Appl. Phys. Lett.Appl. Phys. Lett. %R 10.1063/1.2357605