Local structure plays an dominant role in the structural polymorphsim and novel electronic properties under extreme conditions, but its accurate measurement at high pressure remains a formidable challenge [1-3].
XAFS is a well-known local structural tool, which can provide an upper level resolution in the short order of local structure, but suffers from Bragg reflections of single-crystal diamond anvils [4,5]. Recently we have succeeded in obtain high-quality X-ray absorption fine structure at high pressure[5,6], being able to probe the subtle structural and electronic polymorphs[2,3,7].
We will report our recent progress in the high-pressure XAFS to decipher the puzzling origin of the intriguing electronic states in the isostructural R-3m phase of Bi2Te3 at high pressure. We will show that the combination of accurate local structure is critically important for understanding the isostructural electronic states and the connection between the structure and function as in Bi2Te3 at high pressure .