DC TRANSPORT IN INTENSE, INPLANE TERAHERTZ ELECTRIC-FIELDS IN AL(X)GA(1-X)AS HETEROSTRUCTURES AT 300-K

We report 300 K studies of the dependence of the in-plane, d.c. conduc tivity, sigma(d.c.) (E(omega)), of a quasi 2D electron gas on the ampl itude E(omega) and frequency of intense, far-infrared fields (omega/2p i = 0.24-3.5 THz). We measure sigma(d.c.) (E(omega) parallel-to E(d.c. )), where E(d.c.) is a small sensing field, and observe a monotonic de crease in sigma(d.c.) with increasing E(omega). Although a simple scal ing ansatz collapses the measured sigma(d.c.) (E(omega)) data onto a s ingle curve for frequencies from 0.25-3.45 THz (at low to moderate sca led fields), the decrease in conductivity is substantially more rapid than expected from comparison to similar data taken by Masselink et al . [Solid-St. Electron. 31, 337 (1988)] at 35 GHz. We tentatively attri bute this difference to effects of a high-frequency modulation in the electron temperature.