Intrinsic bistability in resonant-tunneling structures

We calculate in the effective-mass approximation the current-voltage characteristic for an ${\mathrm{Al}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As-GaAs-${\mathrm{Al}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As heterostructure. Our calculation includes the effect of electron-electron interaction in a self-consistent way. We show that charge accumulation in the quantum well is large enough to produce a bistability in the negative-differential-resistance region of the current-voltage curve.