"Pressure tuning the lattice and optical response of silver sulfide"

Zhao Zhao: Hua Wei, and Wendy L. Mao; Applied Physics Letters, 06/27/16.

Additional Authors: Hua Wei, and Wendy L. Mao

Abstract:

Binary transition metal chalcogenides have attracted increasing attention for their unique structural and electronic properties. High pressure is a powerful tool for tuning the lattice and electronic structure of transition metal chalcogenides away from their pristine states. In this work, we systematically studied the in situ structural and optical behavior of silver sulfide (Ag2S) under pressure by synchrotron X-ray diffraction and infrared spectroscopy measurements in a diamond anvil cell. Upon compression, Ag2S undergoes structural symmetrization accompanied by a series of structural transitions while the crystallographic inequivalence of the two Ag sites is maintained. Electronically, pressure effectively tunes the ambient semiconducting Ag2S into a metal at ~22 GPa. Drude model analysis shows that the optical conductivity evolves significantly, reaching the highest value of 100 Ω-1 cm-1 at ~40 GPa. Our results highlight the structural and electronic tunability of silver chalcogenides as a function of pressure and suggest the potential of Ag2S as a platform for developing optical and opto-electronic applications.