High-pressure synthesis of bilayer nickelate SrNiOCl with a tetragonal crystal structure.

Motivated by a theoretical prediction of its potential superconductivity under ambient pressure, a novel oxychloride, SrNiOCl, was synthesized for the first time. This synthesis utilized a high pressure of 10 GPa at 1673 K. Small single crystals were used to determine the crystal structure and measure the temperature dependence of electrical resistance. The crystal is isostructural with the recently discovered superconductor LaNiO, in line with theoretical expectation.