Effect of thermal inhomogeneity for terahertz radiation from intrinsic Josephson junction stacks of Bi2Sr2CaCu2O8+δ

Terahertz radiation from the mesa structures of Bi2Sr2CaCu2O8+δ is detected in samples with thin electrodes <100 nm. In samples with thick electrodes ≃400 nm, neither radiations nor voltage jumps in current-voltage characteristics are detected. This suggests that the thin electrode helps excite the Josephson plasma oscillation as a result of the poor heat flow through the electrode. The shielding effect by the electrode is not essential. We consider that the local temperature rise is the origin of the synchronization of the phase kink for terahertz radiation.