IBM Optimizes Material Capabilities at ALS

A schematic of the crystal structures in vanadium dioxide (VO2), showing the motion of the vanadium (black arrows) with respect to the oxygen ions across the metal-insulator transition. VO2 acts like an insulator at low temperatures but like a metal at near room temperature.

Scientific AchievementIBM researchers used the ALS to understand the link between

electron conduction and lattice distortions in spintronics materials.

Significance and ImpactThe ability to control electron conduction can form the basis for

an ultrafast electronic switch in the future; devices could be activated so quickly that very little energy would be lost through dissipation.

Research Details−Vanadium dioxide is one of the few known materials that acts like an

insulator at low temperatures but like a metal at warmer temperatures. −By varying the thickness of an underlying buffer layer, researchers were able

to change the strain in a vanadium dioxide film and thereby vary the transition temperature between conducting and insulating phases.

−Researchers found that the material's ordering temperature is determined by the orbital occupancy in the high-temperature metallic phase rather than that of the insulating phase.

Work was performed at Lawrence Berkeley National Laboratory, ALS Beamline 4.0.2. The operation of the ALS is supported by the U.S. Department of Energy, Office of Basic Energy Sciences.

Read the full article: www-als.lbl.gov/index.php/science-highlights/industry-als/888