“Phase transitions come in two basic ‘flavors,'” explained Carnegie co-author Guoyin Shen, director of the High-Pressure Collaborative Access Team at the Advanced Photon Source. “In one type, the chemical bonds do not break as the material goes from one phase to another. But they do alter in orientation and length in an orderly manner. The other, called reconstructive phase transition, is more chaotic, but the most prevalent in nature and the focus of this study. In these transitions, parts of the chemical bonds are broken and the structure changes significantly when it enters a new phase.”
|Lin et al|
“The richness in crystalline structure of bismuth is particularly useful for witnessing changes in the structure of a material,” remarked lead author Chuanlong Lin.
“The bismuth displayed a metastable liquid in the process of solid-solid phase transitions under decompression at about 23,000 to 15,000 atmospheres,” Lin said.
“Because reconstructive phase transitions are the most fundamental type, this research provides a brand new way for understanding how different materials change,” Shen said. “It’s possible that other materials could display a similar metastable liquid when they undergo reconstructive transitions and that this phenomenon is more prevalent than we thought. The results will no doubt lead to countless surprises in both materials science and planetary science in the coming years.”