Nanoshells as a high-pressure gauge analyzed to 200 GPa

High pressure structural studies on Nb5Si3 up to 26.2 GPa

New cubic phase of lithium nitride to 200 GPa

We present a new cubic γ (Fm3m) Li3N phase discovered above 40(±5) GPa. Structure and spectral distribution of the cubic phase are examined to 200 GPa with synchrotron x-ray diffraction and inelastic x-ray Raman scattering in a diamond anvil cell. First principles calculations predict a factor-of-five band-gap widening at the onset of the β → γ transition, consistent with an observed color chan...

Sectroscopic Studies of p - H 2 to above 200 GPa

Raman and infrared vibrational spectra of H2 have been measured to pressures in excess of 200 GPa and at liquid helium temperatures using new high sensitivity techniques. Detailed study of the pressure dependence of op conversion rate reveals an initial increase followed by a decrease above 1 GPa. The conversion rate then increases dramatically with pressure, and this continues to above 50 GPa....

A New Cubic Phase of Li3N: Stability of the N 3− Ion to 200 GPa

Diamond anvil cell experiments augmented by first principles calculations have found a remarkable stability of the N3− ion in Li3N to a six-fold volume reduction. A new (γ) phase is discovered above 40(±5) GPa, with an 8% volume collapse and a bandgap quadrupling at the transition determined by synchrotron x-ray diffraction and inelastic x-ray scattering. γ-Li3N (Fm3m, Li3Bi-like structure) rem...

Stability and compressibility of the high-pressure phases of Al2O3 up to 200 GPa: Implications for the electrical conductivity of the base of the lower mantle

We have used a laser-heated diamond anvil cell to investigate the stability and compressibility of Cmcm CaIrO3-type (postperovskite structure) Al2O3 at pressures up to 200 GPa. A phase transformation from the Pbcn Rh2O3(II)-type to the CaIrO3-type structure was observed at 130 GPa, which is consistent with previous theoretical studies. The observed CaIrO3-type structure in Al2O3 is the same as ...