Numerical Simulation of Electronic Behavior in a Finite Superlattice With a Tamm State: A Possible Submillimeter Wave Emitter Without Optical Pumping

ABSTRACTWe propose a semiconductor heterostructure consisting of six coupled quantum wells of GaAs plus a larger one, all inside Al(x)Ga(l−x)As, x=0.35. Our simulation prevents that the localized electronic eigen-state at the large well, the Tamm state, will oscillate when the voltage applied across these “finite superlattice” varies fast. We include exchange and correlation effects in the local density approximation and made the self-consistent calculations to the electrons at 77K varying the voltage in a gate contact of the device. We obtain the effective potential, the sub-bands (mini-bands) and respective electronic densities which enable us to simulate the temporal evolution of an electronic wave-packet when the gate-voltage is switched fast. Such a switching turns the Tamm eigen-state in a wave-packet. By the simulation we conclude that this wave-packet oscillates a Tera-Hertz frequency that can emit electromagnetic radiation as a charge oscillator. We estimate the finite superlattice capacitance and it confirms the possibility of changing the Hamiltonian faster than the period of the oscillation.