Scientists at Caltech and Yale University have introduced a new method to accurately predict the Kondo effect in real materials, a significant advancement in the field of quantum physics. This breakthrough allows researchers to go beyond traditional simplified models that only approximate this complex phenomenon, which involves the interactions of electrons in these materials.
The Kondo effect occurs when a magnetic impurity, such as iron or manganese, is placed in a metal like copper. Below a specific temperature, known as the Kondo temperature, the electrical resistance in the metal behaves unexpectedly: rather than continuously decreasing with cooling, it levels off and then increases. This complexity arises because the magnetic impurity interacts with surrounding electrons, a behavior that is crucial to understanding many quantum materials, including high-temperature superconductors.
The findings were published in the journal Science, with Linqing Peng and Tianyu Zhu from Yale University as the lead authors. Both researchers worked under Garnet Chan, Bren Professor of Chemistry at Caltech and director of the Rudolph A. Marcus Center for Theoretical Chemistry. Chan, who is also the senior author of the paper, stated, “It is now possible to predict the properties of some complicated materials purely through computation without referring to experiment.” He characterized their initial findings as a “baby step” toward addressing more complex phenomena in quantum materials.
The Kondo effect has been a central challenge in physics since the 1970s, requiring the analysis of a vast number of interacting particles. While conventional approaches have relied on simplified orbital models to represent electronic structures, Chan and his team employed advanced computational tools from quantum chemistry to assess the magnetic impurities more accurately. This methodology allows researchers to represent these impurities while retaining the full complexity of their interactions.
In their study, the team analyzed seven different transition-metal atoms embedded in copper, achieving predictions that were up to 100 times more accurate than traditional techniques. “We are in an exciting era in which faithful predictive quantum descriptions of the full chemical complexity of real materials are coming within reach,” Peng noted, highlighting the potential for future breakthroughs in material science. She expressed optimism about using these theoretical advancements to help discover new materials with unique properties, particularly those related to high-temperature superconductivity.
The researchers’ work was supported by the Air Force Office of Scientific Research, the U.S. Department of Energy’s Center for Molecular Magnetic Quantum Materials, and the National Science Foundation. The implications of this study could significantly enhance the design and understanding of complicated quantum materials in the years to come.
