Resonances, Instabilities, and Structure Selection of Driven Josephson Lattice in Layered Superconductors

Abstract

We investigate dynamics of Josephson vortex lattice in layered high Tc superconductors at high magnetic fields. It is shown that the average electric current depends on the lattice structure and is resonantly enhanced when the Josephson frequency matches the frequency of the plasma mode. We find the stability regions of moving lattice. It is shown that a specific lattice structure at given velocity is uniquely selected by the boundary conditions: at small velocities periodic triangular lattice is stable and looses its stability at some critical velocity. At even higher velocities a structure close to a rectangular lattice is restored.

Radiation from Flux Flow in Josephson Junction Structures

“…This instability corresponds to experimentally observed end point of the first flux-flow branch. It was also shown that interaction with top and bottom surfaces leads to significant lattice deformations [41].…”

“…Lattice structures and their stability in this regime in the case of large lateral size l have been addressed in Ref. [41] and have been reconsidered in Ref. [42] with the conclusion that for parameters typical for BSCCO no stable regular lattice exists at high velocities.…”

“…For a static lattice such a configuration minimizes the energy of the magnetic field inside the crystal with large l, N. However, at small l boundary conditions are inconsistent with triangular lattice at some values of bl, and in this case rectangular lattice becomes more favorable [43]. For moving vortex lattice energy consideration does not work, and here the parameters κ n should be determined by the condition that total current I via each junction is the same [41],…”

“…e.g., Ref. [41]) Here we used reduced x coordinate, u = x/λ J normalized to the Josephson length λ J = γs and reduced time, τ = ω p t, where ω p = c/(λ c √ ǫ c ) is the plasma frequency, ǫ c is the c-axis highfrequency dielectric constant inside the superconductor, λ ab and λ c are the London penetration lengths, ℓ ≡ λ ab /s, s is the interlayer distance, and ∇ 2 n notates the discrete second derivative operator, ∇ 2 n A n = A n+1 + A n−1 − 2A n . The dissipation parameters, ν ab = 4πσ ab /(γ 2 ǫ c ω p ) and ν c = 4πσ c /(ǫ c ω p ), are determined to the quasiparticle conductivities, σ ab and σ c , along and perpendicular to the layers, respectively.…”

Coexisting multiple dynamic states generated by magnetic field in Bi 2 Sr 2 CaCu 2 O 8+δ stacked Josephson junctions

“…In this high-field region, JVs configurations in the static state are well understood and are known to be in a triangular lattice [2,3,4,5]. Despite much interest, however, dynamic state of JVs is far less understood although various aspects of dynamical properties are proposed including the possible lattice structures [6,7,8], interaction between JVs and electromagnetic excitations [9,10,11,12], and coherent characters of the JV motion [13] over the whole junctions in a stack.Key elements governing the dynamics of JVs are well reflected in the tunneling current-voltage (I-V) characteristics, which reveal the relation between the driving force acting on JVs in a junction by the bias current and the responsive JVs motion that induces a voltage drop across the junctions. For instance, JV viscosity is determined by the in-and out-of-plane quasiparticle dissipation that is extracted from the tunneling JV-flow resistance [14,15].…”