Polymorphism in Germanium

Researchers Xiao-Jia Chen, Viktor Struzhkin, and Ho-Kwang Mao from Carnegie and Yue Meng from HPCAT, along with collaborators from China, designed delicate experiments to obtain a complete high-pressure phase diagram of compressed Ge. Their results, published in Physical Review Letters, show that under a pressure of 66 GPa, Ge undergoes a structural change from a metallic white tin structure to an orthorhombic Imma structure. It then undergoes another change under pressure of 90 GPa to the simple hexagonal structure. These findings matched with theoretical predictions about the element’s behavior under extreme pressure.

Ge is an important element for semiconductor industry and is fundamental in condensed matter physics. Ge crystal structure changes from the semiconducting diamond-type structure to metallic phases with increasing coordination. As such, accurately determining the structures and transition pressures has been an important goal of high-pressure experimenters. Click here for full article. 

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