home > seminars 2016 > Zack Geballe


Dr. Zack Geballe
Carnegie Fellow, Carnegie Geophysical Laboratory, Washington, DC

Wednesday October 12, 3:30 PM
Thirkield Hall (Physics), room 103

 

Melting, freezing and glass-formation at the extreme pressures found inside the Earth 3.  [PDF]

ABSTRACT: Melting, freezing, and glass formation cause dramatic changes inside the Earth, from convection of molten iron to explosions of magma. Laboratory studies of these physical transformations help constrain models of the Earth, but they also reveal surprising subtleties in condensed matter physics, the main topic of this talk. Rather than follow simple rules of melting and freezing, materials such as iron, silica and water often melt or become glassy under compression, remain metastable liquids upon cooling, and/or recrystallize upon heating. In this talk, I will (1) introduce models of melting, freezing, and glass-formation at high pressure (2) describe a new laboratory technique I developed to refine these models, and (3) show contrasting examples of the stability of glasses at high pressure: glassy H2O is highly sensitive to preparation history, whereas the bulk properties of glassy CaSiO3 are robust to its preparation history.