Perspective article examines conductivity at the LaAlO3 and SrTiO3 (001) interface

Oct 10, 2011

(PhysOrg.com) -- Complex oxides have the potential to inject new functionalities into technologies that require semiconductors.  The correlated behavior of itinerant electrons in these materials sets complex oxides apart from traditional semiconductors such as Si and GaAs. Potential applications abound, but the fundamental properties of these materials, particularly when combined to make interfaces, must be understood.  In an invited Perspective article in Surface Science, Dr. Scott Chambers of PNNL examines conductivity at the interface of polar and nonpolar complex oxides from outside the reigning paradigm and considers how unintentional dopants and defects, resulting from interfacial mixing, might affect the electronic properties.

The common paradigm used to explain the observation of at interfaces of materials such as lanthanum aluminate and strontium titanate is that electrons move across the interface to alleviate the so-called polar catastrophe created by polar/nonpolar interface creation.  Based on a number of different experimental results, Chambers argues that this simple paradigm is inadequate to explain observed conductivity.

"Intermixing occurs, and the resulting cation rearrangement cannot be ignored," said Chambers, a Fellow of the AVS and the American Association for the Advancement of Science. "Moreover, defects and dopants appear to play a role in facilitating, if not enabling conductivity."

Providing insights into the fundamental relationships between composition/structure, and the resulting electronic, magnetic, and surface chemical properties of complex could enable these materials to have an impact on next-generation electronics, chemical sensors, and photocatalysts. These advances could include more energy-efficient field effect transistors and photocatalysts that use visible light from the sun.

Chambers and his colleagues around the world are continuing to make strides in understanding the complex relationships between atom distributions near the interface and conductivity. One upshot is that significantly more insight into the growth process is necessary to characterize and ultimately control defect creation during heterojunction formation.

"Then and only then can structures suspected of facilitating conductivity be changed to see if doing so actually reduces or eliminates conductivity," said Chambers.

Explore further: New star-shaped molecule breakthrough

More information: Chambers SA. 2011. "Understanding the Mechanism of Conductivity at the LaAlO3 and SrTiO3 (001) Interface." Surface Science 605:1133-1140.

add to favorites email to friend print save as pdf

Related Stories

'Impossible' conductivity explained

May 19, 2010

(PhysOrg.com) -- Bring two materials that are not themselves conductive into contact and, exactly at their interface, something remarkable happens: at that precise point, conduction is possible.

Computer model predicts how materials meet in the middle

Mar 16, 2010

(PhysOrg.com) -- Predicting the way different materials fuse together at an atomic level in objects including iPods, computer chips and even ships may be possible using a new computer model, described in the ...

Unexpected magnetism discovered

Oct 18, 2010

Theoretical work done at the Department of Energy's Oak Ridge National Laboratory has provided a key to understanding an unexpected magnetism between two dissimilar materials.

Recommended for you

New star-shaped molecule breakthrough

2 hours ago

(Phys.org) —Scientists at The University of Manchester have generated a new star-shaped molecule made up of interlocking rings, which is the most complex of its kind ever created.

Smartgels are thicker than water

Sep 19, 2014

Transforming substances from liquids into gels plays an important role across many industries, including cosmetics, medicine, and energy. But the transformation process, called gelation, where manufacturers ...

Separation of para and ortho water

Sep 18, 2014

(Phys.org) —Not all water is equal—at least not at the molecular level. There are two versions of the water molecule, para and ortho water, in which the spin states of the hydrogen nuclei are different. ...

User comments : 0