  We propose and verify experimentally a new concept for achieving strong
nonlinear coupling between the electromagnetic and elastic properties in
metamaterials. This coupling is provided through a novel degree of freedom in
metamaterial design: internal rotation within structural elements. Our
meta-atoms have high sensitivity to electromagnetic wave power, and the elastic
and electromagnetic properties can be independently designed to optimise the
response. We demonstrate a rich range of nonlinear phenomena including
self-tuning and bistability, and provide a comprehensive experimental
demonstration of the predicted effects.
