New way to measure quantum materials is a bit MER

"While we have investigated a number of these materials with large magnetoresistance over the decades, we are only just beginning to get a sense of why some materials demonstrate it and not others; here we open the door to a clearer theoretical explanation of their properties."Sergey Bud'ko, Ames Laboratory

Experimental physicists have combined several measurements of quantum materials into one, as part of their ongoing quest to learn more about manipulating and controlling the behavior of these materials for possible applications. They’ve even coined a term for it – magneto-elastoresistance (MER) – as they report in a paper in the Proceedings of the National Academy of Sciences.

Scientists in condensed matter physics at the US Department of Energy's Ames Laboratory have a long history of investigating ‘weird’ materials, according to Paul Canfield, Ames Lab physicist and professor of physics and astronomy at Iowa State University.

‘Weird’ in this case means metallic and semi-metallic compounds with magnetic, superconducting or other properties that might be useful in technology applications such as quantum computing. To force these materials to reveal their secrets, however, experimentalists must poke, prod and measure them to see how, and how much, they react.

Canfield and his fellow researchers systematically studied tungsten ditelluride (WTe₂), a semi-metal, by exposing it to an electric current, a magnetic field, and strain from pushing and pulling. Measurements of resistance under a combination of an external magnetic field and strain was something that had not been studied in any systematic way before.

The researchers found that the material reacted with large changes in elastoresistance, and that it was further controllable by a magnetic field, especially at low temperatures.

By pairing experimental findings with density functional theory and modeling, "we were able to demonstrate that MER is tied to the redistribution of carriers from different bands (i.e. heavy hole band, light hole and electron band)" said Na Hyun Jo, a postdoctoral research associate at Ames Laboratory. "This means engineering WTe₂ and others like it is possible for future applications."

Physicist Sergey Bud'ko, also at Ames and Iowa State University, said he was pleased the experiment showed a large effect in MER, as it proves to the larger scientific community that this is an effective way of looking for similar effects in similar materials and learning how or when they will occur. "While we have investigated a number of these materials with large magnetoresistance over the decades, we are only just beginning to get a sense of why some materials demonstrate it and not others; here we open the door to a clearer theoretical explanation of their properties."

This story is adapted from material from Ames Laboratory, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.