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.

10adetector10adevices10afield-effect transistors10aPhysics10aplasma-waves10aradiation10aresonant detection10asubterahertz10atransport1 aSong, J., W.1 aKabir, N., A.1 aKawano, Y.1 aIshibashi, K.1 aAizin, G., R.1 aMourokh, L.1 aReno, J., L.1 aMarkelz, A., G.1 aBird, J., P. uhttp://markelz.physics.buffalo.edu/node/24301574nas a2200337 4500008004500000020001400045245011100059210006900170260000800239300000600247490000700253520062400260653002900884653002200913653001200935653001700947653001400964653002300978653001701001100001801018700001301036700001701049700001701066700002001083700001701103700001701120700001601137700001801153700001701171856004801188 2006 Engldsh a0003-695100aTerahertz transmission characteristics of high-mobility GaAs and InAs two-dimensional-electron-gas systems0 aTerahertz transmission characteristics of highmobility GaAs and cSep a30 v893 aFrequency-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.

10afield-effect transistors10aphotoconductivity10aPhysics10aplasma-waves10aradiation10aresonant detection10asubterahertz1 aKabir, N., A.1 aYoon, Y.1 aKnab, J., R.1 aChen, J., Y.1 aMarkelz, A., G.1 aReno, J., L.1 aSadofyev, Y.1 aJohnson, S.1 aZhang, Y., H.1 aBird, J., P. uhttp://markelz.physics.buffalo.edu/node/229