Combining a fully switchable THz superconducting metamaterial with a 2DEG for ultra-strong couplingJ. Keller, C. Maissen, G. Scalari, M. Beck, S. Cibella, R. Leoni and J. FaistEur. Phys. J. Plus, 132 11 (2017) 454DOI: https://doi.org/10.1140/epjp/i2017-11731-2