Flat branches and pressure amorphization

Baryonic branches and resolutions of Ricci-flat Kähler cones

We consider deformations of N = 1 superconformal field theories that are AdS/CFT dual to Type IIB string theory on Sasaki-Einstein manifolds, characterised by non-zero vacuum expectation values for certain baryonic operators. Such baryonic branches are constructed from (partially) resolved, asymptotically conical Ricci-flat Kähler manifolds, together with a choice of point where the stack of D3...

Pressure-induced structural evolution and amorphization in Eu3Ga5O12

Amorphization and decomposition of scandium molybdate at high pressure

The behavior of negative thermal-expansion material scandium molybdate Sc2sMoO4d3 is investigated at high pressure (HP) and high temperature (HT) using x-ray diffraction, Raman spectroscopy, and scanning electron microscopy. The compound exhibits unusually high compressibility (bulk modulus ,6 GPa) and undergoes amorphization at 12 GPa. On the other hand, in situ laser heating of amorphous samp...

A New Phase and Pressure Induced Amorphization in Silica

Using first principles variable cell shape molecular dynamics, we predict a new structure for silica. This structure results from annealing a-quartz at pressures near a major phonon instability. The new phase is obtained by rotations of SiO4 tetrahedra producing edge-sharing SiO6 octahedra and SiO5 cuboids. This type of mechanism was proposed to account for structural transitions in silicate me...

HIGH-PRESSURE CRYSTAL CHEMISTRY AND AMORPHIZATION OF e-QUARTZ

Single-crystal X-ray diffraction experiments on e-quartz at pressures to 15 GPa reveal structural instabilities that result in its gradual transition to an amorphous state. With increasing pressure the average Si-O distance ( ~ 1.61 + 0.01/~) and S i O 4 tetrahedral volume (,,~2.14 ___ 0.02.~ 3) remain constant. Compression of e-quartz results from a dramatic decrease in Si-O-Si angle and corre...