Layer-number-dependence of teraherz radiations from intrinsic Josephson junctions stacks

Ota, Yukihiro; Machida, Masahiko  

Since the observation of teraherz emission from mesas made of layered high-Tc superconductor BiSrCaCuO, the mechanism of radiation attracts a great deal of attention from theoretical and engineering points of view. Emission has a connection with the dynamical aspects of superconducting phases and electromagnetic wave; constructing a theoretical approach to integrating these degrees of freedom is desirable. A way to resolving the issues is built up by 3D dynamical simulations of intrinsic Josephson junction stacks with outside-vacuum contributions. In this article, we apply our code to characterizing teraherz emission in low-bias-current regions. The highlight is to achieve the change of the junction numbers involved the sample. We successfully reproduce the emergence of -kink behaviors. Then, we show the presence of a critical value of the number of junctions for a strong emission.