Scientists show how a crystal can become a conductor

Washington, Feb 6 : A new research has used computational modeling to show how a crystal of manganese oxide can be changed from an electrical insulator to a conductive metal.

Carried out at the University of California, Davis, this research was conducted by Warren Pickett, professor of physics at UC Davis, and his colleagues.

According to Pickett, "Manganese oxide is magnetic but does not conduct electricity under normal conditions because of strong interactions between the electrons surrounding atoms in the crystal."

"But under pressures of about a million atmospheres (one megabar), manganese oxide transitions to a metallic state," he added.

Using the model, the researchers were able to test different explanations for the transition and identify the microscopic mechanism responsible.

They found that when the atoms are forced together under high pressure, the magnetic properties of the manganese atoms become unstable and collapse, freeing the electrons to move through the crystal.

"The results represent an advance in computer modeling of these materials and could shed light on the behavior of similar minerals deep in the Earth," said Pickett.

Manganese oxide has similar properties to iron oxide and silicates (silicon oxides), which make up a major part of the Earth's crust and mantle.

"Understanding how these materials behave under enormous pressures deep underground could help geologists understand the Earth's interior," said Pickett.

ANI