Date: 25/08/2013

Vanadium dioxide explored as a very-fast switch between insulator/conductor

Physics researchers at the University of Washington are experimenting with a material called vanadium dioxide to find its triple point properties. The triple point is a condition at which the material can exist in different states. Researchers are trying to find the switching properties of vanadium dioxide from conductor to insulator. vanadium dioxide is known for switching rapidly in as little as one 10-trillionth of a second from an electrical insulator to a conductor.

“These solid-state triple points are fiendishly difficult to study, essentially because the different shapes of the solid phases makes it hard for them to match up happily at their interfaces,” said David Cobden, a University of Washington physics professor. “There are, in theory, many triple points hidden inside a solid, but they are very rarely probed.”

Vanadium dioxide is researched back in 1959 by Bell labs for its ability to rearrange electrons and shift from an insulated gate conductor, but 20 years later the researchers realised there are two slightly different insulating fields.

This new research shows that those two insulating phases and the conducting phase in solid vanadium dioxide can coexist stably at 65 degrees Celsius, give or take a tenth of a degree (65 degrees C is equal to 149 degrees Fahrenheit).

Cobden's team made a nano wire using vanadium dioxide. While watching the careful stretching of nano wire with a microscope they observed the triple point.
Researchers noticed when the material manifested its triple point, no force was being applied, the wires were neither stretched nor compressed.
Author: Srinivasa Reddy N