Lifetime of metastable states in resonant tunneling structures

We investigate the transport of electrons through a double-barrier resonant-tunneling structure in the regime where the current-voltage characteristics exhibit bistability. In this regime one of the states is metastable, and the system eventually switches from it to the stable state. We show that the mean switching time tau grows exponentially as the voltage V across the device is tuned from the boundary value V-th into the bistable region. In samples of small area we find ln tauproportional to\V-V-th\(3/2), while in larger samples ln tauproportional to\V-V-th\.