Numerical study on effects of surface impedance and external magnetic fields in THz wave emission from intrinsic Josephson junctions

Numerical study on effect of the surface impedance Z in THz wave emission from intrinsic Josephson junctions reveals that there exist dynamical phase transitions between the McCumber-like state (stable for low Z and low bias current J) and π-phase-kink states (stable for most parameter regions and the number of kinks n depends on J), and the dynamical phase diagram in the Z-J plane is evaluated. When external in-plane magnetic fields are further applied, simple scaling relations hold at emission peaks in the McCumber-like state, while nontrivial emission behaviors are observed in the π-phase-kink states. Field dependence of the n = 1 emission peak varies significantly as Z changes, which can be used for experimental evaluation of Z.