超导-常规介质界面的可调表面等离激元

Tuable Surface Plasmon Polartions at a Superconductor-Medium Interface

研究了环境温度对超导材料和常规介质分界面处的表面等离激元色散曲线和特征长度的影响.结果表明:表面等离激元沿界面传播波矢的最大值和传播距离对温度变化极为敏感,均随环境温度的升高而迅速减小,但表面等离激元在超导材料中的穿透深度却随温度升高而增大.同时,表面等离激元波长与其在常规介质中的穿透深度还与频率有关,处于低频段时,两者都随着温度的升高而减小,而处于高频段时,两者却随着温度升高而增大.利用超导二流体模型的电子超导态和正常态转换机制对该现象进行了理论解释.

The effects of environment temperature on the dispersion relations and characteristic lengths of surface plasmon polar- tions （SPPs） at a superconductor- medium interface are analyzed. The results show that as the temperature increases, the maximal SPPs propagation wave vector and propagation length are greatly decreased, and the penetration depth into supercon- ductor slightly increases. Moreover, the SPPs wavelength and penetration depth into medium are also to do with the frequency, both decrease as the temperature increases in the lower frequency domain, however, they increase with the increase of tempera- ture in the higher frequency domain. The tunable SPPs properties are ascribed to the conversion mechanism between normal state and superconducting state based on superconducting two -fluid model.