title: Quantum cascade phenomenon in Bi2Sr2CaCu2O(8+delta) single crystals.
abstract: We study interlayer transport in Bi2Sr2CaCu2O(8+delta) cuprates, which represent stacks of atomic scale intrinsic Josephson junctions. A series of resonant dips in conductance is observed at condition when bremsstrahlung and recombination bands in nonequilibrium spectrum of Josephson junctions overlap. The phenomenon is explained in terms of self-detection of a new type of collective strongly nonequilibrium state in natural atomic superlattices, bearing certain resemblance with operation of a quantum cascade laser. Conclusions are supported by in situ generation-detection experiments and by numerical simulations.
authors.affiliation: Department of Physics, Stockholm University, AlbaNova University Center, SE-10691 Stockholm, Sweden.
authors.forename: V M
authors.initials: VM
authors.lastname: Krasnov