D.C. transport in intense, in-plane terahertz electric fields in Al_xGa_1-xAs heterostructures at 300 K

We report 300 K studies of the dependence of the in-plane, d.c. conductivity, σ_d.c. (E_ω), of a quasi 2D electron gas on the amplitude E_ω and frequency of intense, far-infrared fields (ω/2π = 0.24-3.5 THz). We measure σ_d.c. (E_ω∥E_d.c.), where E_d.c. is a small sensing field, and obser monotonic decrease in σ_d.c. with increasing E_ω. Although a simple scaling ansatz collapses the measured σ_d.c. (E_ω) data onto a single curve for frequencies from 0.25-3.45 THz (at low to moderate scaled 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 attribute this difference to effects of a high-frequency modulation in the electron temperature.