Abstract: It has been known for many years that the layered high-Tc superconductor BSCCO-2212 behaves as a stack of intrinsic Josephson junctions (IJJs). Stimulated by a recent success in exciting coherent terahertz (THz) electromagnetic (EM) waves from a mesa of BSCCO single crystal, we have performed computer simulations on the coupled sine-Gordon equations which describe the superconductivity phase dynamics and electromagnetic oscillations in IJJs. We have found a new solution to the coupled sine-Gordon equations, which is characterized by a stack of alternating plus and minus π phase kinks along the c axis. Rotated by the applied voltage due to the ac Josephson Effect, these π kinks transform dc energy into cavity electromagnetic oscillation via the nonlinearity of dc Josephson Effect, and emit EM waves in THz band from the surface of the single crystal.

The work is supported by WPI Initiative for Materials Nanoarchitectonics, MEXT, Japan and CREST, JST.

 

References:
[1] S.-Z. Lin and X. Hu, Phys. Rev. Lett. Vol.100, 247006 (2008).
[2] X. Hu and S.-Z. Lin, Supercond. Sci. Tech. Vol.23, 253001 (2010) [topical review].