Pressure-Induced Superconductivity and Flattened Se Rings in the Wide Band Gap Semiconductor CuISe.

The two major classes of unconventional superconductors, cuprates and Fe-based superconductors, have magnetic parent compounds, are layered, and generally feature square-lattice symmetry. We report the discovery of pressure-induced superconductivity in a nonmagnetic and wide band gap 1.95 eV semiconductor, CuISe, with a unique anisotropic structure composed of two types of distinct molecules: Se rings and CuI dimers, which are linked in a three-dimensional framework.

Image analysis of speckle patterns as a probe of melting transitions in laser-heated diamond anvil cell experiments.

The precision of melting curve measurements using laser-heated diamond anvil cell (LHDAC) is largely limited by the correct and reliable determination of the onset of melting. We present a novel image analysis of speckle interference patterns in the LHDAC as a way to define quantitative measures which enable an objective determination of the melting transition. Combined with our low-temperature customized IR pyrometer, designed for measurements down to 500 K, our setup allows studying the melting curve of materials with low melting temperatures, with relatively high precision.