Soft x-ray resonant scattering at the Ni L 2,3 edges is used to test models of magnetic-and orbital-ordering below the metal-insulator transition in NdNiO 3 . The large branching ratio of the L 3 to L 2 intensities of the (1/2 0 1/2) reflection and the observed azimuthal angle and polarization dependence originates form a non-collinear magnetic structure. The absence of an orbital signal and the non-collinear magnetic structure show that the nickelates are materials for which orbital ordering is absent at the metal-insulator transition.

A computational scheme for the investigation of complex materials with strongly interacting electrons is formulated which is able to treat atomic displacements, and hence structural relaxation, caused by electronic correlations. It combines ab initio band structure and dynamical mean-field theory and is implemented in terms of plane-wave pseudopotentials. The equilibrium Jahn-Teller distortion and antiferro-orbital order found for paramagnetic KCuF3 agree well with experiment.

We provide direct evidence that irradiation of a graphene membrane on Ir with low-energy Ar ions induces formation of solid noble-gas nanobubbles. Their size can be controlled by thermal treatment, reaching tens of nanometers laterally and height of 1.5 nm upon annealing at 1080 °C. Ab initio calculations show that Ar nanobubbles are subject to pressures reaching tens of GPa, their formation being driven by minimization of the energy cost of film distortion and loss of adhesion.