How to Turn Crystals From Insulators to Conductors?

A new study argues that by exerting extreme levels of pressure on insulating crystals, they could be turned into excellent electrical conductors. Manganese oxide, a mineral found in Earth's crust is not an electricity conductor under normal atmospheric pressure and temperature conditions, but, when subjected to pressures close to those experienced deep inside the Earth, it becomes one.

The study has been conducted at UC Davis by professor of physics Warren Pickett, by performing advanced computer simulations on the behavior of insulating crystals when under extreme levels of pressure. Pickett claims that his work could be used successfully to create an image of the behavior of minerals deep inside the Earth.

While being subjected to pressures reaching as much as one million atmospheres, the manganese oxide mineral suffers a sudden transition to a metallic state. Previously, there was no model explaining what really happens throughout the transition process, but, by collaborating with colleague Richard Scalettar and a number of other physics researchers from the University of Augsburg, Ural State University and the Institute of Metal Physics, Pickett was able to show that, under extremely high pressures, manganese oxide suffers a severe atoms compaction which would eventually render the atoms of the mineral unstable. Ultimately, the atoms experience a collapse, when electrons are freed and are allowed to move through the whole volume of the crystal.

The process of choosing the material for the experiment came naturally, as manganese oxide has properties relatively similar to that of iron oxide and silicates, that compose most of the crust and mantle of the Earth. Understanding the microscopic mechanism that is responsible for the insulator to conductor transition, effectively opens a door towards understanding how minerals deep inside the Earth behave while being subjected to high pressures, invaluable information for geologist trying to study the inner regions of our planet.