Coherent tunneling of mixed state hole wave packets in coupled quantum well structures

Abstract

The time-dependent Schrödinger equation is solved numerically to study the coherent tunneling of hole wave packets in asymmetric coupled quantum wells. The importance of selection rules and band mixing is evident in the extremely low rates of the wave-packet leakage from heavy-hole state to a resonant light-hole state at zero in-plane wave vector (k∥). But these rates increase dramatically away from k∥=0, when the hole states acquire mixed character, and rapidly become comparable to the heavy-hole to heavy-hole resonant tunneling rates. The effect of inhomogeneous level broadening arising from well size fluctuations in multicoupled quantum well systems is shown to greatly reduce the effective tunneling rates near resonance.