"Pressure-induced structural transitions and metallization in Ag2Te"

Zhao Zhao: Shibing Wang, Haijun Zhang, and Wendy L. Mao; Physical Review B, 07/31/13.

Additional Authors: Shibing Wang, Haijun Zhang, and Wendy L. Mao

Abstract:

High-pressure in situ synchrotron x-ray diffraction experiments were performed on Ag2Te up to 42.6 GPa at room temperature, and four phases were identified. Phase I (β–Ag2Te) transformed into isostructural phase II at 2.4 GPa, and phase III and phase IV emerged at 2.8 and 12.8 GPa, respectively. Combined with first-principles calculations, we solved the phase II and phase III crystal structures and determined the compressional behavior of phase III. Electronic band structure calculations show that the insulating phase I with a narrow band gap first transforms into the semimetallic phase II with the perseverance of topologically nontrivial nature and then to the bulk metallic phase III. Density of states calculations indicate the contrasting transport behavior for Ag2−δTe and Ag2+δTe under compression. Our results highlight pressure’s dramatic role in tuning Ag2Te’s electronic band structure and its novel electrical and magnetotransport behaviors.