CURRENT-VOLTAGE CHARACTERISTICS OF A TUNNEL JUNCTION WITH RESONANT CENTERS

We calculate the I-V characteristics of a tunnel junction containing i mpurities in the barrier. We consider the indirect resonant tunneling involving the impurities. The Coulomb repulsion energy E(c) between tw o electrons with opposite spins simultaneously residing on the impurit y is introduced by an Anderson Hamiltonian. At low temperatures T much -less-than E(c) the I-V characteristic is linear in V both for V < E(c ) and for V > E(c) and changes slope at V = E(c). This behavior reflec ts the energy spectrum of the impurity electrons-the finite value of t he charging energy E(c). At T approximately E(c) the junction reveals an Ohmic-like behavior as a result of the smearing out of the charging effects by the thermal fluctuations.