Theory of intrinsic bistability in double-barrier resonant-tunneling structures

We studied intrinsic bistability in a double-barrier resonant-tunneling structure using the nonequilibrium Schwinger-Keldysh formalism. We derive and solve a nonlinear equation for the charge density in the quantum well and the current as a function of bias voltage and charge density. We calculated the I-V curves for a typical GaAs/(Al,Ga)As double-barrier structure at different temperature. The effect of temperature and resonant-energy-level broadening (including scattering effect) on the intrinsic bistability is discussed. Tristable behavior is shown to be unlikely and probably a computational artifact.