Laser-induced suppression of electron tunneling in a biased asymmetric double quantum well

Laser-induced suppression of electron tunneling in a biased asymmetric double-quantum-well structure is numerically studied based on the Markoff master equation. A pump pulse is used to prepare initially the electronic wave packet which is irradiated by a cw laser. It is shown that if the bias voltage is adjusted to align the upper two electronic states in the narrow well and the wide well, suppression can occur before dephasing is complete. An analytical expression for the time evolution of the wave packet is derived by a degenerate-two-level model to give a qualitative interpretation to the origin of the electron localization.