Ultrafast structural dynamics of the Fe-pnictide parent compound BaFe2As2

Understanding the interplay of the various degrees of freedom such as the electrons, spins and lattice is essential for many complex materials, including the high-temperature superconductors. In the case of the Fe pnictides, especially the strong sensitivity of the electronic and magnetic properties to the exact shape and size of the Fe-As tetrahedra (Fig. 1, left) plays a crucial role for superconductivity and demonstrates a strong magneto-structural coupling. In addition, antiferromagnetic phases are closely linked to structural distortions in these materials.