Andreev scattering of quasiparticle wave packets and current-voltage characteristics of superconducting metallic weak links

Journal Article · Sat Sep 01 00:00:00 EDT 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.3992· OSTI ID:6228730

Kuemmel, R; Gunsenheimer, U ^[1]; Nicolsky, R ^[2]

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1. Physikalisches Institut der Universitaet Wuerzburg, Wuerzburg (Germany)
2. Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21945 Rio de Janeiro (Brazil)

Current-voltage characteristics (CVC's) of superconductor--normal-conductor--superconductor junctions and their dependence on temperature and mean free path are calculated in a relaxation-time model for quasiparticles moving in a constant electric field between the walls of the pair potential well. By forming wave packets from the nonequilibrium electron and hole solutions of the time-dependent Bogoliubov--de Gennes equations, a detailed microscopic picture of quasiparticle acceleration and electron-hole (Andreev) scattering is obtained. Computing the time-averaged current density from these wave packets, one obtains the characteristic features of experimentally observed CVC's in microbridges, {ital SNS} sandwiches, and point contacts (including such with high-{Tc} superconductors). They are the foot'' at low voltages {ital V}{much lt}{Delta}/{ital e}, negative differential conductivity, and subharmonic gap structure (SGS) for {ital V}{le}2{Delta}/{ital en}, {ital n}=1,2,3,..., and the excess current if {ital eV} is much larger than the maximum value {Delta} of the pair potential. Pronounced arches appear for voltages in the SGS regime, if one takes into account the weakening of Andreev reflection by normal scattering from the outer surfaces of relatively thin {ital S} layers. The theory is valid at any temperature below {Tc} and for any mean free path.

• OSTI ID: 6228730
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:7; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

656100* -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
JUNCTIONS
PHYSICAL PROPERTIES
QUASI PARTICLES
SCATTERING
SUPERCONDUCTING JUNCTIONS
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
WAVE PACKETS
WAVE PROPAGATION