Tunnelling through two barriers

M. M. T. M. Dierichs, Pieter Dieleman, J. J. Wezelman +2 more

Double-barrier Nb/Al2O3/Al/Al2O3/Nb tunnel junctions are used as mixing elements in a 345 GHz waveguide mixer. Noise temperatures (double side band) down to 720 K at 3.0 K are obtained without the need to apply a magnetic field to suppress the Josephson current. It is shown that the composite barrier acts as a single barrier for photon-assisted tunneling. Surprisingly, at these frequencies the capacitance of two stacked tunnel barriers is only determined by one barrier.

P.N. Roy, P.N. Singh, D.K. Roy

Ekaterina A. Volkova, A. M. Popov, Olga V. Tikhonova

The tunneling of a quantum system with an internal degree of freedom through a potential barrier is considered. Based on the exact numerical solution to the nonstationary Schrödinger equation, the tunneling of a model two-particle system through a potential barrier is studied and the dependences of the tunneling transparency of the barrier on the parameters of the wave packet that describes the system at the initial moment are obtained. A sharp increase in the tunneling probability related to the formation of a long-lived quasibound state of the system in the barrier region is demonstrated. A simple analytical model of the tunneling of a system with an internal degree of freedom that allows for a qualitative interpretation of the main features of the tunneling is constructed.

Zhuangqi Cao, Cheng Yin

Aleksandr K. Zaichenko

The method of calculation of the transmission coefficient and tunneling time of particles through a double barrier is proposed which takes into account the irreversibility of wave packets spreading. The resonance values of the transmission coefficient and tunneling time of neutrons through two barriers are calculated. The obtained value of tunneling time is compared with the experimental results.

Daniela Mugnai, Anedio Ranfagni, Lawrence S. Schulman