Material properties can be changed just by altering shape, study shows

Scientists have shown that it is possible to change properties of a material by simply altering its shape. The work by scientists at U.S. Department of Energy’s (DOE) Argonne National Laboratory made the findings based on their work with thin film of metal oxide known as titania.

Researchers say that when the transport of electrons and ions of a material are confined, it is possible to alter the properties of material – enhanced to be precise – thereby paving way for next-gen applications in the field of electronics. Scientists observed that in confined space, electrons travel like waves through materials and when they collide and interact due to confined space, they can give rise to new patterns that can be harnessed to our advantage.

In the case of titania, it caused electrons to interfere with each other in a unique pattern, which increased the oxide’s conductivity, or the degree to which it conducts electricity. Normally, when an electric current is applied to an oxide like titania, electrons flow through the material in a simple wave form. At the same time, ions — or charged particles — also move around. These processes give rise to the material’s electronic transport properties, such as conductivity and resistance, which are exploited in the design of next-generation electronics.

To start, researchers created films of titania, then engineered a pattern on them. In the pattern were holes that were a mere 10 to 20 nanometers apart. Adding the geometric pattern altered the movement of electrons the same way that throwing rocks into a body of water alters the waves that ripple through it. In the case of titania, the pattern caused electron waves to interfere with each other, which led the oxide to conduct more electricity.

This all happened at the mesoscale, a scale where scientists can see both quantum effects and the movement of electrons and molecules.

In all, this work offers scientists more insight about how atoms, electrons and other particles behave at the quantum level. Such information could aid in designing new materials that can process information and be useful in other electronic applications.

The researchers investigated conductivity and other properties using two techniques: electron holography and electron energy loss spectroscopy. To that end, they leveraged resources at Argonne’s Center for Nanoscale Materials (CNM), a DOE Office of Science User Facility, to fabricate their samples and make some of the measurements.

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