Bismuth Iodide Crystals (IMAGE) University of Texas at Dallas Caption University of Texas at Dallas scientists are very experienced in growing these large, high-quality bismuth iodide crystals to study their physical properties. When the flat, needle-like crystals come out of the furnace where they are grown, they are rooted together at one end. The crystals, which are about 1 centimeter in length, take about three weeks to grow but must be annealed for several months before they are ready for study. Research published Aug. 24, 2021, online in Physical Review X demonstrates clearly for the first time that crystals made from bismuth and iodine in UT Dallas laboratories are not only weak topological insulators, but also undergo a phase transition into a novel structure at room temperature that significantly alters the material’s electronic properties. Credit University of Texas at Dallas Usage Restrictions with credit License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.