Atsunori Sakurai, Yoshitaka Tanimura
The quantum dissipative dynamics of a tunneling process through double barrier structures is investigated on the basis of a rigorous treatment. We employ a Caldeira-Leggett Hamiltonian with an effective potential calculated self-consistently, accounting for the electron distribution. With this Hamiltonian, we use the reduced hierarchy equations of motion in the Wigner space representation to study non-Markovian and non-perturbative thermal effects at finite temperature in a rigorous manner. We study the current-voltage relation of the resonant tunneling diode for several widths of the contact region, which consists of doped GaAs. Hysteresis and both single and double plateau-like behavior are observed in the negative differential resistance (NDR) region. While all of the current oscillations decay in time in the NDR region in the case of a strong system-bath coupling, there exist non-transient oscillations in some parts of the plateau in the NDR region in the case of weak coupling. We find that the effective potential in the oscillating case possesses a basin-like form on the emitter side (emitter basin) and that the current oscillation results from tunneling between the emitter basin and the quantum well in the barriers. We find two distinct types of current oscillations, with large and small oscillation amplitudes, respectively. The results of eigenstates analysis indicate that the first type is caused by a transition between ground tunneling states and adjacent excited states in the emitter basin, while the second type is caused by a transition between intermediate tunneling states and higher states. These two types of oscillation also appear differently in the Wigner space, with one exhibiting tornado-like motion and the other exhibiting a two piston engine-like motion.
View original:
http://arxiv.org/abs/1304.5596
No comments:
Post a Comment