ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Most tunnel barriers contain localized electronic states nl(Δx, ε) in large amounts decreasing with distance Δx from the metal. The localized states hybridize with conduction electrons forming interface states with a decay width Δl∝exp(−2Δxκ) and a correlation energy ΔU* ∝ 1/εrΔx. For ΔU*〉Δl these states are localized, which yields a strong coupling to surface plasmons, phonons, and spins. These states cause diffuse surface scattering and enhance exponentially [∝ Δ−1l ∝exp(+2Δxκ)] the tunnel matrix element by resonant tunneling jR as compared to tunneling jφ¯ through the whole potential barrier φ¯. Consequently at voltages ||eU|| 〈φ¯, jR(U,T) is identified by its stronger U and T dependencies and can even dominate over jφ¯. The enhanced interaction of the localized electrons with surface plasmons, phonons, and spins yield strong U, T, and time dependencies in the tunnel current which produce giant zero-bias anomaly and spin-flip zero-bias anomaly; capacitance changes; inelastic processes, noise, and barrier reduction with increasing temperature; and pair weakening, leakage current, and reduction of the Josephson current.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.336100
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