Full multiple scattering calculations on HgTe under high pressure at the mercury L_3 X-ray absorption EDGE

摘要

HgTe crystallizes in the zincblende structure at ambient pressure, transforming to a cinnabar structure at 1.5 GPa, at 300K, and then to a rocksalt structure at 8 GPa. Simultaneously to pressure-induced structural changes, transitions from semi-metal->semi-conductor->metal occur. The zincblende-> cinnabar->rocksalt transition leads to important changes in the shape of the XANES spectra~1 at the Hg L_3 edge. The goal of these Full Multiple Scattering (FMS) calculations based on a real-space cluster methods is threefold: we first want to reproduce the XANES modifications observed under increasing pressure, then confirm the atomic positions determined elsewhere by angular dispersive X-ray diffraction (ADX) and XAS~(1,2) by using these data for the construction of the cluster and finaly address XANES resonances as fingerprints of the different structures.