[S-MP44] [JJ] Physics and Chemistry of Minerals

[SMP44-01] Single crystal elasticity of gold (Au) up to ~20 GPa: Bulk modulus anomaly below ~5 GPa and implication for a primary pressure scale

*Akira Yoneda¹, Hiroshi Fukui², Gomi Hitoshi¹, Seiji Kamada⁴, Longjian Xie¹, Naohisa Hirao⁵, Hiroshi Uchiyama⁵, Satoshi Tsutsui⁵, Alfred Baron³ (1.Institute for Planetary Materials, Okayama University, 2.Graduate School of Material Science, University of Hyogo, 3.Materials Dynamics Laboratory, RIKEN SPring-8 Center, 4.Graduate School of Science, Tohoku University, 5.Japan Synchrotron Radiation Research Institute)

Keywords:gold, single crystal elasticity, bulk modulus, pressure scale, inelastic X ray scattwering, diamond anvil cell

We measured single crystal elasticity of gold (Au) as well as its lattice parameters simultaneously under high pressure by using inelastic X ray scattering (IXS) technique. Generated pressure and elastic moduli of gold were obtained only from the present experimental data at five pressure points between 0 and 20 GPa by direct numerical integration. Pressure variation of the bulk modulus displays an anomalous behavior; it is nearly constant up to ~5 GPa, and then steeply increases toward higher pressure. Similar anomaly is observed in independent first-principles calculations as well. The absolute pressure scale determined from the present results gives systematically lower pressures than those from the previous pressure scales owing to the bulk modulus anomaly founded in this study.