Unusual behaviour of the conductance in Gaussian superlattices

We study the conductance at finite temperature of pass-band GaAs-Al(x)Ga(1−xAs) superlattices with Gaussian modulated Al mole fraction. Such structures present bands of almost unscattered electronic states and high peak-to-valley ratio in the j–V characteristic. We found a critical point, indicating the onset for the transition from the conducting to the nonconducting regime, by tuning the chemical potential in the vicinity of the band of unscattered states. Remarkably, the conductance of the Gaussian superlattice remains finite around the critical point even at zero temperature.