Terahertz Metamaterials with Semiconductor Split-Ring Resonators for   Magnetostatic Tunability
  We studied a metasurface constituted as a periodic array of semiconductor split-ring resonators. The resonance frequencies of the metasurface excited by normally incident light were found to be continuously tunable in the terahertz regime through an external magnetostatic field of suitable orientation. As such metasurfaces can be assembled into 3D metamaterials, the foregoing conclusion also applies to metamaterials comprising semiconductor split-ring resonators. 
Jiaguang Han, Akhlesh Lakhtakia, and Cheng-Wei Qiu