Topological quantization of current in quantum tunnel contacts
S. A. Bulgadaev
Landau Institute for Theoretical Physics RAS, 142432 Chernogolovka, Moscow Region, Russia
PACS: 73.21.La, 73.23.Hk, 73.40.Gk, 74.50.+r
It is shown that an account of the Berry phase (a topological
θ-term) together with a dissipative term in the effective action S[φ] of the tunnel contacts
induces a strong quantization of the tunnel current at low temperatures.
This phenomenon like the Coulomb blockade reflects a discrete charge
structure of the quantum shot noise and can ensure a quantization of the
tunnel current without a capacitive charging energy EC, when the latter is
strongly suppressed by quantum fluctuations. Since a value of the
θ-parameter is determined by the gate voltage, this effect allows to
control a current through the contact. A possible physical application of
this effect is proposed.