An illustration of a Monte Carlo simulation, where a calculation is run billions of times in slightly different ways to arrive at a range of possible results (far right), which are then averaged to determine the exact result. Each colored line represents a different run. Image: Greg Stewart/SLAC National Accelerator Laboratory.
An illustration of a Monte Carlo simulation, where a calculation is run billions of times in slightly different ways to arrive at a range of possible results (far right), which are then averaged to determine the exact result. Each colored line represents a different run. Image: Greg Stewart/SLAC National Accelerator Laboratory.

Strange metals make interesting bedfellows with high-temperature superconductors, which can carry electricity with zero loss.

Both are rule-breakers. Strange metals don't behave like regular metals, whose electrons act independently; instead their electrons behave in some unusual collective manner. For their part, high-temperature superconductors can operate at much higher temperatures than conventional superconductors; how they do this is still unknown.

In many high-temperature superconductors, changing the temperature or the number of free-flowing electrons in the material can flip it from a superconducting state to a strange metal state or vice versa. Scientists are trying to find out how these states are related, part of a 30-year quest to understand how high-temperature superconductors work so they can be developed for a host of potential applications, from maglev trains to perfectly efficient power transmission lines.

Now, in a paper in Science, theorists with the Stanford Institute for Materials and Energy Sciences (SIMES) at the US Department of Energy's SLAC National Accelerator Laboratory report that they have observed strange metallicity in the Hubbard model. This is a longstanding model for simulating and describing the behavior of materials with strongly correlated electrons, meaning the electrons join forces to produce unexpected phenomena such as superconductivity, rather than acting independently.

Although the Hubbard model has been studied for decades, with some hints of strange metallic behavior, this is the first time that strange metallicity has been seen in Monte Carlo simulations, in which billions of separate and slightly different calculations are averaged to produce an unbiased result. This is important because the physics of these systems can change drastically and without warning if any approximations are introduced.

The SIMES team was also able to observe strange metallicity at the lowest temperatures ever explored with an unbiased method – temperatures at which the conclusions from their simulations are much more relevant for experiments. The scientists said their work provides a foundation for connecting theories of strange metals to models of superconductors and other strongly correlated materials.

This story is adapted from material from SLAC National Accelerator 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.