Nonlinear Nonequilibrium Quasiparticle Relaxation in Josephson Junctions
2009 (English)In: Physical Review Letters, ISSN 0031-9007, Vol. 103, no 22, 227002- p.Article in journal (Refereed) Published
I solve numerically a full set of nonlinear kinetic balance equations for stacked Josephson junctions, which allows analysis of strongly nonequilibrium phenomena. It is shown that nonlinearity becomes significant already at very small disequilibrium. The following new, nonlinear effects are obtained: (i) At even-gap voltages V=2n/e (n=2,3,…) nonequilibrium bosonic bands overlap. This leads to enhanced emission of =2 bosons and to the appearance of dips in tunnel conductance. (ii) A new type of radiative solution is found at strong disequilibrium. It is characterized by the fast stimulated relaxation of quasiparticles. A stack in this state behaves as a light emitting diode and directly converts electric power to boson emission, without utilization of the ac-Josephson effect. The phenomenon can be used for realization of a new type of superconducting cascade laser in the THz frequency range.
Place, publisher, year, edition, pages
2009. Vol. 103, no 22, 227002- p.
lasing, Josephson junction, THz emission
Condensed Matter Physics
Research subject Physics
IdentifiersURN: urn:nbn:se:su:diva-32119DOI: 10.1103/PhysRevLett.103.227002ISI: 000272182000046OAI: oai:DiVA.org:su-32119DiVA: diva2:279489