Body-Centered-Cubic Phase Transformation in Gold at TPa Pressures

In situ x-ray diffraction at both the National Ignition Facility and Omega-EP Laser Facility has been utilized to determine the crystallographic state of ramp and shock-ramp compressed gold up to 1.2 TPa (1 TPa=10 Mbar=10×10⁶ atmospheres). In this Letter, we describe a series of experiments that explore a variety of pressure-temperature states in Au, accessed using tailored laser pulses. We find that the ambient pressure face-centered-cubic phase is stable under ramp compression to pressures of at least 1 TPa where the body-centered-cubic phase is observed simultaneously.